diff --git a/packages/shared/src/components/ProfileMenu/sections/ExtensionSection.tsx b/packages/shared/src/components/ProfileMenu/sections/ExtensionSection.tsx
index 2b33380290..7f2188bb79 100644
--- a/packages/shared/src/components/ProfileMenu/sections/ExtensionSection.tsx
+++ b/packages/shared/src/components/ProfileMenu/sections/ExtensionSection.tsx
@@ -10,15 +10,11 @@ import { useLazyModal } from '../../../hooks/useLazyModal';
 import { LazyModal } from '../../modals/common/types';
 import { checkIsExtension } from '../../../lib/func';
 
-export const ExtensionSection = (): ReactElement | null => {
+const ExtensionSectionContent = (): ReactElement => {
   const { openModal } = useLazyModal();
   const { isActive: isDndActive, setShowDnd } = useDndContext();
   const { optOutCompanion, toggleOptOutCompanion } = useSettingsContext();
 
-  if (!checkIsExtension()) {
-    return null;
-  }
-
   return (
     <>
       <HorizontalSeparator />
@@ -33,7 +29,7 @@ export const ExtensionSection = (): ReactElement | null => {
           {
             title: `${isDndActive ? 'Resume' : 'Pause'} new tab`,
             icon: isDndActive ? PlayIcon : PauseIcon,
-            onClick: () => setShowDnd?.(true),
+            onClick: () => setShowDnd(true),
           },
           {
             title: `${optOutCompanion ? 'Enable' : 'Disable'} companion widget`,
@@ -45,3 +41,11 @@ export const ExtensionSection = (): ReactElement | null => {
     </>
   );
 };
+
+export const ExtensionSection = (): ReactElement | null => {
+  if (!checkIsExtension()) {
+    return null;
+  }
+
+  return <ExtensionSectionContent />;
+};
diff --git a/packages/shared/src/contexts/AlertContext.tsx b/packages/shared/src/contexts/AlertContext.tsx
index ab31232653..3126578948 100644
--- a/packages/shared/src/contexts/AlertContext.tsx
+++ b/packages/shared/src/contexts/AlertContext.tsx
@@ -2,7 +2,7 @@ import type { ReactNode, ReactElement } from 'react';
 import React, { useMemo, useContext } from 'react';
 import type { UseMutateAsyncFunction } from '@tanstack/react-query';
 import { useMutation } from '@tanstack/react-query';
-import type { Alerts, AlertsUpdate } from '../graphql/alerts';
+import type { Alerts } from '../graphql/alerts';
 import {
   UPDATE_ALERTS,
   UPDATE_LAST_BOOT_POPUP,
@@ -13,36 +13,33 @@ import { gqlClient } from '../graphql/common';
 
 export const ALERT_DEFAULTS: Alerts = {
   filter: true,
-  rankLastSeen: null,
-  myFeed: null,
+  rankLastSeen: undefined,
+  myFeed: undefined,
   squadTour: true,
   showGenericReferral: false,
   showStreakMilestone: false,
   showAchievementUnlock: null,
-  lastBootPopup: null,
-  briefBannerLastSeen: null,
+  lastBootPopup: undefined,
+  briefBannerLastSeen: undefined,
 };
 
 export interface AlertContextData {
   alerts: Alerts;
   isFetched?: boolean;
   loadedAlerts?: boolean;
-  updateAlerts?: UseMutateAsyncFunction<
+  updateAlerts: UseMutateAsyncFunction<unknown, unknown, Alerts, unknown>;
+  updateLastReferralReminder?: UseMutateAsyncFunction<unknown, unknown, void>;
+  updateLastBootPopup?: UseMutateAsyncFunction<unknown, unknown, void>;
+  updateHasSeenOpportunity?: UseMutateAsyncFunction<
     unknown,
     unknown,
-    AlertsUpdate,
-    () => Promise<void>
+    boolean | void
   >;
-  updateLastReferralReminder?: UseMutateAsyncFunction;
-  updateLastBootPopup?: UseMutateAsyncFunction;
-  updateHasSeenOpportunity?: UseMutateAsyncFunction;
-  clearOpportunityAlert?: UseMutateAsyncFunction;
+  clearOpportunityAlert?: UseMutateAsyncFunction<unknown, unknown, void>;
 }
 
-const AlertContext = React.createContext<AlertContextData>({
-  alerts: ALERT_DEFAULTS,
-  loadedAlerts: false,
-});
+// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+const AlertContext = React.createContext<AlertContextData>(null!);
 
 export interface AlertContextProviderProps {
   children: ReactNode;
@@ -60,6 +57,10 @@ export const AlertContextProvider = ({
   isFetched,
   updateAlerts,
 }: AlertContextProviderProps): ReactElement => {
+  const applyUpdatedAlerts = (updatedAlerts: Alerts): void => {
+    updateAlerts?.(updatedAlerts);
+  };
+
   const { mutateAsync: updateRemoteAlerts } = useMutation<
     unknown,
     unknown,
@@ -69,15 +70,15 @@ export const AlertContextProvider = ({
       gqlClient.request(UPDATE_ALERTS, {
         data: params,
       }),
-    onMutate: (params) => updateAlerts({ ...alerts, ...params }),
+    onMutate: (params) => applyUpdatedAlerts({ ...alerts, ...params }),
 
     onError: (_, params) => {
-      const rollback = Object.keys(params).reduce(
+      const rollback = (Object.keys(params) as Array<keyof Alerts>).reduce(
         (values, key) => ({ ...values, [key]: alerts[key] }),
-        {},
+        {} as Alerts,
       );
 
-      updateAlerts({ ...alerts, ...rollback });
+      applyUpdatedAlerts({ ...alerts, ...rollback });
     },
   });
 
@@ -89,16 +90,16 @@ export const AlertContextProvider = ({
     mutationFn: () => gqlClient.request(UPDATE_LAST_BOOT_POPUP),
 
     onMutate: () =>
-      updateAlerts({
+      applyUpdatedAlerts({
         ...alerts,
         lastBootPopup: new Date(),
         bootPopup: false,
       }),
 
     onError: () => {
-      updateAlerts({
+      applyUpdatedAlerts({
         ...alerts,
-        lastBootPopup: null,
+        lastBootPopup: undefined,
         bootPopup: true,
       });
     },
diff --git a/packages/shared/src/contexts/AuthContext.tsx b/packages/shared/src/contexts/AuthContext.tsx
index b9386a03d0..e3df5d2ce4 100644
--- a/packages/shared/src/contexts/AuthContext.tsx
+++ b/packages/shared/src/contexts/AuthContext.tsx
@@ -51,7 +51,7 @@ export interface AuthContextData {
   shouldShowLogin: boolean;
   showLogin: ({ trigger, options }: ShowLoginParams) => void;
   closeLogin: () => void;
-  loginState?: LoginState;
+  loginState?: LoginState | null;
   logout: (reason: string) => Promise<void>;
   updateUser: (user: LoggedUser) => Promise<void>;
   loadingUser?: boolean;
@@ -75,7 +75,8 @@ export interface AuthContextData {
 }
 
 const isExtension = checkIsExtension();
-const AuthContext = React.createContext<AuthContextData>(null);
+// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+const AuthContext = React.createContext<AuthContextData>(null!);
 export const useAuthContext = (): AuthContextData => useContext(AuthContext);
 export default AuthContext;
 
@@ -93,10 +94,11 @@ export const REGISTRATION_PATH = '/register';
 export const logout = async (reason: string): Promise<void> => {
   await dispatchLogout(reason);
   const params = getQueryParams();
-  if (params.redirect_uri) {
-    window.location.replace(params.redirect_uri);
+  const redirectUri = params.redirect_uri;
+  if (redirectUri) {
+    window.location.replace(redirectUri);
   } else if (window.location.pathname === REGISTRATION_PATH) {
-    window.location.replace(process.env.NEXT_PUBLIC_WEBAPP_URL);
+    window.location.replace(process.env.NEXT_PUBLIC_WEBAPP_URL ?? '/');
   }
 
   if (isExtension) {
@@ -107,9 +109,15 @@ export const logout = async (reason: string): Promise<void> => {
 };
 
 export function checkIfGdprCovered(geo?: Boot['geo']): boolean {
+  const region = geo?.region;
+
+  if (!region) {
+    return true;
+  }
+
   return (
     geo?.continent === Continent.Europe ||
-    !outsideGdpr.includes(geo?.region) ||
+    !outsideGdpr.includes(region) ||
     isIOSNative()
   );
 }
@@ -152,7 +160,7 @@ export const AuthContextProvider = ({
   isAndroidApp,
 }: AuthContextProviderProps): ReactElement => {
   const [loginState, setLoginState] = useState<LoginState | null>(null);
-  const endUser = user && 'providers' in user ? user : null;
+  const endUser = user && 'providers' in user ? user : undefined;
   const referral = user?.referralId || user?.referrer;
   const referralOrigin = user?.referralOrigin;
   const router = useRouter();
@@ -169,10 +177,15 @@ export const AuthContextProvider = ({
     logout(LogoutReason.IncomleteOnboarding);
   }
 
-  const isValidRegion = useMemo(
-    () => !invalidPlusRegions.includes(geo?.region),
-    [geo?.region],
-  );
+  const isValidRegion = useMemo(() => {
+    const region = geo?.region;
+
+    if (!region) {
+      return true;
+    }
+
+    return !invalidPlusRegions.includes(region);
+  }, [geo?.region]);
 
   return (
     <AuthContext.Provider
@@ -185,7 +198,7 @@ export const AuthContextProvider = ({
         referralOrigin: loginState?.referralOrigin ?? referralOrigin,
         firstVisit: user?.firstVisit,
         trackingId: user?.id,
-        shouldShowLogin: loginState !== null,
+        shouldShowLogin: !!loginState,
         showLogin: useCallback(
           ({ trigger, options = {} }) => {
             const hasCompanion = !!isCompanionActivated();
diff --git a/packages/shared/src/contexts/BootProvider.spec.tsx b/packages/shared/src/contexts/BootProvider.spec.tsx
index aba2441505..7bdee76c37 100644
--- a/packages/shared/src/contexts/BootProvider.spec.tsx
+++ b/packages/shared/src/contexts/BootProvider.spec.tsx
@@ -53,7 +53,7 @@ beforeEach(() => {
   localStorage.clear();
 });
 
-const defaultAlerts: Alerts = { filter: true, rankLastSeen: null };
+const defaultAlerts: Alerts = { filter: true, rankLastSeen: undefined };
 
 const defaultSettings: RemoteSettings = {
   theme: 'bright',
@@ -162,7 +162,13 @@ const SettingsMock = ({
         Sidebar
       </button>
       <button
-        onClick={() => setTheme(toTheme)}
+        onClick={() => {
+          if (!toTheme) {
+            return;
+          }
+
+          setTheme(toTheme);
+        }}
         type="button"
         data-test-value={themeMode}
       >
@@ -176,14 +182,20 @@ const SettingsMock = ({
         Show Weekly Goal widget
       </button>
       <button
-        onClick={() => setSpaciness(toSpaciness)}
+        onClick={() => {
+          if (!toSpaciness) {
+            return;
+          }
+
+          setSpaciness(toSpaciness);
+        }}
         type="button"
         data-test-value={spaciness}
       >
         Spaciness
       </button>
       <button
-        onClick={() => toggleInsaneMode(toInsaneMode)}
+        onClick={() => toggleInsaneMode(toInsaneMode ?? false)}
         type="button"
         data-test-value={insaneMode}
       >
@@ -391,7 +403,13 @@ const AuthMock = ({ updatedUser, loginTrigger }: AuthMockProps) => {
   return (
     <>
       <button
-        onClick={() => updateUser(updatedUser)}
+        onClick={() => {
+          if (!updatedUser) {
+            return;
+          }
+
+          updateUser(updatedUser);
+        }}
         type="button"
         data-test-value={user?.name || 'anonymous'}
       >
@@ -404,7 +422,9 @@ const AuthMock = ({ updatedUser, loginTrigger }: AuthMockProps) => {
         Logout
       </button>
       <button
-        onClick={() => showLogin({ trigger: loginTrigger })}
+        onClick={() =>
+          showLogin({ trigger: loginTrigger ?? AuthTriggers.Comment })
+        }
         type="button"
         data-test-value={JSON.stringify(loginState)}
       >
diff --git a/packages/shared/src/contexts/BootProvider.tsx b/packages/shared/src/contexts/BootProvider.tsx
index 0d90274ffc..00b110e3ab 100644
--- a/packages/shared/src/contexts/BootProvider.tsx
+++ b/packages/shared/src/contexts/BootProvider.tsx
@@ -41,6 +41,14 @@ const ConnectionError = dynamic(
     ),
 );
 
+const getStorageItem = (key: string): string | null => {
+  return storage.getItem?.(key) ?? null;
+};
+
+const setStorageItem = (key: string, value: string): void => {
+  storage.setItem?.(key, value);
+};
+
 function filteredProps<T extends Record<string, unknown>>(
   obj: T,
   filteredKeys: (keyof T)[],
@@ -61,9 +69,9 @@ export type BootDataProviderProps = {
 };
 
 export const getLocalBootData = (): BootCacheData | null => {
-  const local = storage.getItem(BOOT_LOCAL_KEY);
+  const local = getStorageItem(BOOT_LOCAL_KEY);
   if (local) {
-    return JSON.parse(storage.getItem(BOOT_LOCAL_KEY)) as BootCacheData;
+    return JSON.parse(local) as BootCacheData;
   }
 
   return null;
@@ -87,14 +95,20 @@ const updateLocalBootData = (
     'isAndroidApp',
   ]);
 
-  storage.setItem(BOOT_LOCAL_KEY, JSON.stringify(result));
+  setStorageItem(BOOT_LOCAL_KEY, JSON.stringify(result));
 
   return result;
 };
 
-const getCachedOrNull = () => {
+const getCachedOrNull = (): Partial<BootCacheData> | null => {
   try {
-    return JSON.parse(storage.getItem(BOOT_LOCAL_KEY));
+    const cached = getStorageItem(BOOT_LOCAL_KEY);
+
+    if (!cached) {
+      return null;
+    }
+
+    return JSON.parse(cached) as Partial<BootCacheData>;
   } catch (err) {
     return null;
   }
@@ -135,7 +149,7 @@ export const BootDataProvider = ({
     );
   };
 
-  const [initialLoad, setInitialLoad] = useState<boolean>(null);
+  const [initialLoad, setInitialLoad] = useState<boolean>();
   const [cachedBootData, setCachedBootData] = useState<Partial<Boot>>();
 
   useEffect(() => {
@@ -148,7 +162,7 @@ export const BootDataProvider = ({
     const boot = getLocalBootData();
 
     if (!boot) {
-      setCachedBootData(null);
+      setCachedBootData(undefined);
 
       return;
     }
@@ -157,14 +171,17 @@ export const BootDataProvider = ({
       applyTheme(themeModes[boot.settings.theme]);
     }
 
-    preloadFeedsRef.current({ feeds: boot.feeds, user: boot.user });
+    preloadFeedsRef.current?.({ feeds: boot.feeds, user: boot.user });
 
     setCachedBootData(boot);
   }, [localBootData]);
 
   const { hostGranted } = useHostStatus();
   const isExtension = checkIsExtension();
-  const logged = cachedBootData?.user as LoggedUser;
+  const logged =
+    cachedBootData?.user && 'providers' in cachedBootData.user
+      ? cachedBootData.user
+      : undefined;
   const shouldRefetch = !!logged?.providers && !!logged?.id;
   const lastAppliedChangeRef = useRef<Partial<BootCacheData>>();
 
@@ -180,7 +197,7 @@ export const BootDataProvider = ({
     queryFn: async () => {
       const pathname = globalThis?.location?.pathname;
       const result = await getBootData({ app, pathname });
-      preloadFeedsRef.current({ feeds: result.feeds, user: result.user });
+      preloadFeedsRef.current?.({ feeds: result.feeds, user: result.user });
 
       return result;
     },
@@ -194,8 +211,14 @@ export const BootDataProvider = ({
   const { user, settings, alerts, notifications, squads, geo, isAndroidApp } =
     cachedBootData || {};
 
-  useRefreshToken(remoteData?.accessToken, refetch);
-  const updatedAtActive = user ? dataUpdatedAt : null;
+  useRefreshToken(
+    remoteData?.accessToken ?? {
+      token: '',
+      expiresIn: new Date(0).toISOString(),
+    },
+    refetch,
+  );
+  const updatedAtActive = user ? dataUpdatedAt : 0;
   const updateBootData = useCallback(
     (updatedBootData: Partial<BootCacheData>, update = true) => {
       const cachedData = getCachedOrNull() || {};
@@ -216,7 +239,7 @@ export const BootDataProvider = ({
         if (cachedData?.lastModifier !== 'companion' && lastAppliedChange) {
           updatedData = { ...updatedData, ...lastAppliedChange };
         }
-        lastAppliedChangeRef.current = null;
+        lastAppliedChangeRef.current = undefined;
       }
 
       const updated = updateLocalBootData(cachedData, updatedData);
@@ -236,31 +259,31 @@ export const BootDataProvider = ({
   );
 
   const updateSettings = useCallback(
-    (updatedSettings) => updateBootData({ settings: updatedSettings }),
+    (updatedSettings: BootCacheData['settings']) =>
+      updateBootData({ settings: updatedSettings }),
     [updateBootData],
   );
 
   const updateAlerts = useCallback(
-    (updatedAlerts) => updateBootData({ alerts: updatedAlerts }),
+    (updatedAlerts: BootCacheData['alerts']) =>
+      updateBootData({ alerts: updatedAlerts }),
     [updateBootData],
   );
 
-  const updateExperimentation = useCallback(
-    (exp: BootCacheData['exp']) => {
-      updateLocalBootData(cachedBootData, { exp });
-    },
-    [cachedBootData],
-  );
+  const updateExperimentation = useCallback((exp: BootCacheData['exp']) => {
+    const cachedData = getCachedOrNull() ?? {};
+    updateLocalBootData(cachedData, { exp });
+  }, []);
 
   if (logged?.language && logged?.isPlus) {
-    gqlClient.setHeader('content-language', logged.language as string);
+    gqlClient.setHeader('content-language', logged.language);
   } else {
     gqlClient.unsetHeader('content-language');
   }
 
   useEffect(() => {
     if (remoteData) {
-      setInitialLoad(initialLoad === null);
+      setInitialLoad(initialLoad === undefined);
       updateBootData(remoteData);
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps
@@ -303,10 +326,12 @@ export const BootDataProvider = ({
     );
   }
 
+  const growthBookUser = user ?? remoteData?.user ?? { id: 'anonymous' };
+
   return (
     <GrowthBookProvider
       app={app}
-      user={user}
+      user={growthBookUser}
       deviceId={deviceId}
       experimentation={cachedBootData?.exp}
       updateExperimentation={updateExperimentation}
diff --git a/packages/shared/src/contexts/DndContext.tsx b/packages/shared/src/contexts/DndContext.tsx
index b2c9bae20a..4ace6cf28b 100644
--- a/packages/shared/src/contexts/DndContext.tsx
+++ b/packages/shared/src/contexts/DndContext.tsx
@@ -1,4 +1,4 @@
-import type { Dispatch, ReactElement, ReactNode } from 'react';
+import type { Dispatch, ReactElement, ReactNode, SetStateAction } from 'react';
 import React, { useContext, useState } from 'react';
 import usePersistentContext from '../hooks/usePersistentContext';
 import { checkIsExtension } from '../lib/func';
@@ -6,42 +6,28 @@ import { checkIsExtension } from '../lib/func';
 export type DndSettings = { expiration: Date; link: string };
 
 export interface DndContextData {
-  setShowDnd: Dispatch<boolean>;
+  setShowDnd: Dispatch<SetStateAction<boolean>>;
   showDnd: boolean;
-  dndSettings: DndSettings;
+  dndSettings?: DndSettings;
   isActive: boolean;
   onDndSettings: (settings: DndSettings) => Promise<void>;
 }
 
-const DEFAULT_VALUE = {
-  showDnd: null,
-  setShowDnd: null,
-  dndSettings: null,
-  isActive: false,
-  onDndSettings: null,
-};
-const DndContext = React.createContext<DndContextData>(DEFAULT_VALUE);
+// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+const DndContext = React.createContext<DndContextData>(null!);
 const now = new Date();
 
 interface DndContextProviderProps {
   children: ReactNode;
 }
 
-export const DndContextProvider = ({
+const ExtensionDndContextProvider = ({
   children,
 }: DndContextProviderProps): ReactElement => {
   const [showDnd, setShowDnd] = useState(false);
   const [dndSettings, setDndSettings] =
     usePersistentContext<DndSettings>('dnd');
 
-  if (!checkIsExtension()) {
-    return (
-      <DndContext.Provider value={DEFAULT_VALUE}>
-        {children}
-      </DndContext.Provider>
-    );
-  }
-
   return (
     <DndContext.Provider
       value={{
@@ -57,6 +43,16 @@ export const DndContextProvider = ({
   );
 };
 
+export const DndContextProvider = ({
+  children,
+}: DndContextProviderProps): ReactElement => {
+  if (!checkIsExtension()) {
+    return <>{children}</>;
+  }
+
+  return <ExtensionDndContextProvider>{children}</ExtensionDndContextProvider>;
+};
+
 export default DndContext;
 
 export const useDndContext = (): DndContextData => useContext(DndContext);
diff --git a/packages/shared/src/contexts/FeedContext.tsx b/packages/shared/src/contexts/FeedContext.tsx
index a37ceda143..4cb2ace28e 100644
--- a/packages/shared/src/contexts/FeedContext.tsx
+++ b/packages/shared/src/contexts/FeedContext.tsx
@@ -45,7 +45,7 @@ const baseFeedSettings: Record<FeedSettingsKeys, FeedSettings> = {
       eco: 1,
       roomy: 1,
     },
-    adTemplate: featureFeedAdTemplate.defaultValue.default,
+    adTemplate: featureFeedAdTemplate.defaultValue?.default ?? { adStart: 2 },
   },
   tablet: {
     pageSize: 9,
@@ -136,19 +136,27 @@ export function FeedLayoutProvider({
   }, [sidebarExpanded]);
 
   const { feedSettings, defaultFeedSettings } = useMemo(() => {
-    const enhancedFeedSettings = Object.entries(baseFeedSettings).reduce(
+    const enhancedFeedSettings = (
+      Object.entries(baseFeedSettings) as Array<
+        [FeedSettingsKeys, FeedSettings]
+      >
+    ).reduce<Record<FeedSettingsKeys, FeedSettings>>(
       (acc, [feedSettingsKey, feedSettingsValue]) => {
+        const featureAdTemplate =
+          feedAdTemplateFeature.value?.[feedSettingsKey];
+        const fallbackAdTemplate = feedAdTemplateFeature.value?.default;
+
         acc[feedSettingsKey] = {
           ...feedSettingsValue,
-          adTemplate:
-            feedAdTemplateFeature.value[feedSettingsKey] ||
-            feedAdTemplateFeature.value.default,
+          adTemplate: featureAdTemplate ?? fallbackAdTemplate,
         };
 
         return acc;
       },
-      {},
-    ) as typeof baseFeedSettings;
+      {
+        ...baseFeedSettings,
+      },
+    );
 
     return {
       feedSettings: [
@@ -165,9 +173,11 @@ export function FeedLayoutProvider({
   // Generate the breakpoints for the feed settings
   // Uses debounced sidebar state to sync layout change with sidebar animation
   const feedBreakpoints = useMemo(() => {
-    const breakpoints = feedSettings.map((setting) =>
-      setting.breakpoint.replace('@media ', ''),
-    );
+    const breakpoints = feedSettings
+      .filter((setting): setting is FeedSettings & { breakpoint: string } => {
+        return !!setting.breakpoint;
+      })
+      .map((setting) => setting.breakpoint.replace('@media ', ''));
 
     if (!sidebarRendered) {
       return breakpoints;
diff --git a/packages/shared/src/contexts/NotificationsContext.tsx b/packages/shared/src/contexts/NotificationsContext.tsx
index 8edeac3958..707d89d4b9 100644
--- a/packages/shared/src/contexts/NotificationsContext.tsx
+++ b/packages/shared/src/contexts/NotificationsContext.tsx
@@ -8,8 +8,9 @@ export interface NotificationsContextData {
   incrementUnreadCount: () => void;
 }
 
-const NotificationsContext =
-  React.createContext<NotificationsContextData>(null);
+const NotificationsContext = React.createContext<NotificationsContextData>(
+  null!, // eslint-disable-line @typescript-eslint/no-non-null-assertion
+);
 
 export default NotificationsContext;
 
diff --git a/packages/shared/src/contexts/PushNotificationContext.tsx b/packages/shared/src/contexts/PushNotificationContext.tsx
index 9dc24bda8c..a2bdcf4da3 100644
--- a/packages/shared/src/contexts/PushNotificationContext.tsx
+++ b/packages/shared/src/contexts/PushNotificationContext.tsx
@@ -35,15 +35,9 @@ export interface PushNotificationsContextData {
 }
 
 export const PushNotificationsContext =
-  createContext<PushNotificationsContextData>({
-    isPushSupported: false,
-    isInitialized: true,
-    isSubscribed: false,
-    isLoading: false,
-    shouldOpenPopup: () => true,
-    subscribe: null,
-    unsubscribe: null,
-  });
+  createContext<PushNotificationsContextData>(
+    null!, // eslint-disable-line @typescript-eslint/no-non-null-assertion
+  );
 
 interface PushNotificationContextProviderProps {
   children: ReactElement;
@@ -71,10 +65,15 @@ function OneSignalSubProvider({
     isFetched,
     isLoading,
     isSuccess,
-  } = useQuery<typeof OneSignal>({
+  } = useQuery<typeof OneSignal | undefined>({
     queryKey: key,
 
     queryFn: async () => {
+      const userId = user?.id;
+      if (!userId) {
+        return undefined;
+      }
+
       const osr = client.getQueryData<typeof OneSignal>(key);
 
       if (osr) {
@@ -83,15 +82,20 @@ function OneSignalSubProvider({
 
       const OneSignalImport = (await import('react-onesignal')).default;
 
+      const appId = process.env.NEXT_PUBLIC_ONESIGNAL_APP_ID;
+      if (!appId) {
+        return undefined;
+      }
+
       await OneSignalImport.init({
-        appId: process.env.NEXT_PUBLIC_ONESIGNAL_APP_ID,
+        appId,
         serviceWorkerParam: { scope: '/push/onesignal/' },
         serviceWorkerPath: '/push/onesignal/OneSignalSDKWorker.js',
       });
 
-      await OneSignalImport.login(user.id);
+      await OneSignalImport.login(userId);
 
-      setIsSubscribed(OneSignalImport.User.PushSubscription.optedIn);
+      setIsSubscribed(!!OneSignalImport.User.PushSubscription.optedIn);
 
       return OneSignalImport;
     },
@@ -174,7 +178,7 @@ function OneSignalSubProvider({
         isInitialized: !isEnabled || isFetched || !isSuccess,
         isLoading,
         isSubscribed,
-        isPushSupported: isPushSupported && isSuccess && isEnabled,
+        isPushSupported: !!(isPushSupported && isSuccess && isEnabled),
         shouldOpenPopup: () => {
           const { permission } = globalThis.Notification ?? {};
           return permission === 'denied';
@@ -201,12 +205,17 @@ function NativeAppleSubProvider({
     queryKey: key,
 
     queryFn: async () => {
+      const userId = user?.id;
+      if (!userId) {
+        return;
+      }
+
       const promise = promisifyEventListener('push-state', (event) => {
         setIsSubscribed(!!event?.detail);
       });
       postWebKitMessage(WebKitMessageHandlers.PushState, null);
-      postWebKitMessage(WebKitMessageHandlers.PushUserId, user.id);
-      return promise;
+      postWebKitMessage(WebKitMessageHandlers.PushUserId, userId);
+      await promise;
     },
     enabled: isEnabled,
     ...disabledRefetch,
@@ -266,9 +275,7 @@ export function PushNotificationContextProvider({
   const isExtension = checkIsExtension();
 
   if (isExtension) {
-    throw new Error(
-      'PushNotificationContextProvider should only be used in the webapp',
-    );
+    return <>{children}</>;
   }
 
   if (isIOSNative()) {
diff --git a/packages/shared/src/contexts/SettingsContext.tsx b/packages/shared/src/contexts/SettingsContext.tsx
index 249d51075d..b0eae64af0 100644
--- a/packages/shared/src/contexts/SettingsContext.tsx
+++ b/packages/shared/src/contexts/SettingsContext.tsx
@@ -73,7 +73,8 @@ export interface SettingsContextData extends Omit<RemoteSettings, 'theme'> {
   applyThemeMode: (mode?: ThemeMode) => void;
 }
 
-const SettingsContext = React.createContext<SettingsContextData>(null);
+// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+const SettingsContext = React.createContext<SettingsContextData>(null!);
 export default SettingsContext;
 
 const deprecatedLightModeStorageKey = 'showmethelight';
@@ -143,13 +144,23 @@ const defaultSettings: RemoteSettings = {
   },
 };
 
+const defaultSettingsFlags: SettingsFlags = {
+  sidebarSquadExpanded: true,
+  sidebarCustomFeedsExpanded: true,
+  sidebarOtherExpanded: true,
+  sidebarResourcesExpanded: true,
+  sidebarBookmarksExpanded: true,
+  clickbaitShieldEnabled: true,
+  defaultWriteTab: WriteFormTab.NewPost,
+};
+
 export const SettingsContextProvider = ({
   children,
   settings = defaultSettings,
   updateSettings,
   loadedSettings,
 }: SettingsContextProviderProps): ReactElement => {
-  const setTheme = useRef<ThemeMode>(null);
+  const setTheme = useRef<ThemeMode | undefined>();
   const { user } = useContext(AuthContext);
   const userId = user?.id;
   const { unsubscribePersonalizedDigest } = usePersonalizedDigest();
@@ -165,7 +176,7 @@ export const SettingsContextProvider = ({
   const { mutateAsync: updateRemoteSettings } = useMutation<
     unknown,
     unknown,
-    RemoteSettings
+    Partial<RemoteSettings>
   >({
     mutationFn: (params) =>
       gqlClient.request(UPDATE_USER_SETTINGS_MUTATION, {
@@ -173,12 +184,14 @@ export const SettingsContextProvider = ({
       }),
 
     onError: (_, params) => {
-      const rollback = Object.keys(params).reduce(
+      const rollback = (
+        Object.keys(params) as Array<keyof RemoteSettings>
+      ).reduce(
         (values, key) => ({ ...values, [key]: settings[key] }),
-        {},
+        {} as Partial<RemoteSettings>,
       );
 
-      updateSettings({ ...settings, ...rollback });
+      updateSettings?.({ ...settings, ...rollback });
     },
   });
 
@@ -187,7 +200,7 @@ export const SettingsContextProvider = ({
       if (mode) {
         setTheme.current = mode;
       } else {
-        setTheme.current = null;
+        setTheme.current = undefined;
       }
 
       applyTheme(setTheme.current || themeModes[settings.theme]);
@@ -196,14 +209,14 @@ export const SettingsContextProvider = ({
   );
 
   useEffect(() => {
-    const lightMode = storageWrapper.getItem(deprecatedLightModeStorageKey);
+    const lightMode = storageWrapper.getItem?.(deprecatedLightModeStorageKey);
     if (lightMode === 'true') {
       applyTheme(ThemeMode.Light);
     }
   }, []);
 
   const updateRemoteSettingsFn = async (
-    newSettings: RemoteSettings,
+    newSettings: Partial<RemoteSettings>,
     bootUserId?: string,
   ): Promise<void> => {
     if (userId || bootUserId) {
@@ -213,8 +226,10 @@ export const SettingsContextProvider = ({
     }
   };
 
-  const setSettings = async (newSettings: RemoteSettings): Promise<void> => {
-    updateSettings({ ...settings, ...newSettings });
+  const setSettings = async (
+    newSettings: Partial<RemoteSettings>,
+  ): Promise<void> => {
+    updateSettings?.({ ...settings, ...newSettings });
     await updateRemoteSettingsFn(newSettings);
   };
 
@@ -222,6 +237,8 @@ export const SettingsContextProvider = ({
     await updateRemoteSettingsFn(settings, bootUserId);
   };
 
+  const settingsFlags: SettingsFlags = settings.flags ?? defaultSettingsFlags;
+
   const contextData = useMemo<SettingsContextData>(
     () => ({
       ...settings,
@@ -276,7 +293,7 @@ export const SettingsContextProvider = ({
               ? CampaignCtaPlacement.ProfileMenu
               : CampaignCtaPlacement.Header,
         }),
-      loadedSettings,
+      loadedSettings: loadedSettings ?? false,
       updateCustomLinks: (links: string[]) =>
         setSettings({ ...settings, customLinks: links }),
       updateSortCommentsBy: (sortCommentsBy: SortCommentsBy) =>
@@ -285,7 +302,7 @@ export const SettingsContextProvider = ({
         setSettings({
           ...settings,
           flags: {
-            ...settings.flags,
+            ...settingsFlags,
             [flag]: value,
           },
         }),
@@ -293,17 +310,17 @@ export const SettingsContextProvider = ({
         updateRemoteSettingsFn({
           ...settings,
           flags: {
-            ...settings.flags,
+            ...settingsFlags,
             [flag]: value,
           },
         }),
-      updatePromptFlag: (flag: keyof SettingsFlags, value: boolean) =>
+      updatePromptFlag: (flag: string, value: boolean) =>
         setSettings({
           ...settings,
           flags: {
-            ...settings.flags,
+            ...settingsFlags,
             prompt: {
-              ...settings.flags.prompt,
+              ...(settingsFlags.prompt ?? {}),
               [flag]: value,
             },
           },
@@ -313,7 +330,7 @@ export const SettingsContextProvider = ({
     }),
     // @NOTE see https://dailydotdev.atlassian.net/l/cp/dK9h1zoM
     // eslint-disable-next-line react-hooks/exhaustive-deps
-    [settings, loadedSettings, userId, applyThemeMode],
+    [settings, settingsFlags, loadedSettings, userId, applyThemeMode],
   );
 
   return (
diff --git a/packages/shared/src/contexts/SubscriptionContext.tsx b/packages/shared/src/contexts/SubscriptionContext.tsx
index 4f26793177..fd8d4dbd6d 100644
--- a/packages/shared/src/contexts/SubscriptionContext.tsx
+++ b/packages/shared/src/contexts/SubscriptionContext.tsx
@@ -6,12 +6,12 @@ import ProgressiveEnhancementContext from './ProgressiveEnhancementContext';
 import AuthContext from './AuthContext';
 
 export interface SubscriptionContextData {
-  subscriptionClient: Client;
+  subscriptionClient?: Client;
   connected: boolean;
 }
 
 const SubscriptionContext = React.createContext<SubscriptionContextData>({
-  subscriptionClient: null,
+  subscriptionClient: undefined,
   connected: false,
 });
 export default SubscriptionContext;
@@ -27,21 +27,27 @@ export const SubscriptionContextProvider = ({
   const { tokenRefreshed, accessToken } = useContext(AuthContext);
 
   const [connected, setConnected] = useState(false);
-  const [subscriptionClient, setSubscriptionClient] = useState<Client>(null);
+  const [subscriptionClient, setSubscriptionClient] = useState<Client>();
 
   useEffect(() => {
+    const accessTokenValue = accessToken?.token;
+
+    if (!accessTokenValue) {
+      return;
+    }
+
     if (windowLoaded && tokenRefreshed && !subscriptionClient) {
       requestIdleCallback(() => {
         import(
           /* webpackChunkName: "subscriptions" */ '../graphql/subscriptions'
         ).then(({ createSubscriptionClient }) => {
-          const client = createSubscriptionClient(accessToken?.token);
+          const client = createSubscriptionClient(accessTokenValue);
           setSubscriptionClient(client);
           client.on('connected', () => setConnected(true));
         });
       });
     }
-  }, [windowLoaded, tokenRefreshed, accessToken, subscriptionClient]);
+  }, [windowLoaded, tokenRefreshed, accessToken?.token, subscriptionClient]);
 
   const contextData = useMemo<SubscriptionContextData>(
     () => ({
diff --git a/packages/shared/src/contexts/WritePostContext.tsx b/packages/shared/src/contexts/WritePostContext.tsx
index 52f2b3d84c..58d4a92404 100644
--- a/packages/shared/src/contexts/WritePostContext.tsx
+++ b/packages/shared/src/contexts/WritePostContext.tsx
@@ -57,17 +57,8 @@ export interface WritePostProps {
   formId?: string;
 }
 
-export const WritePostContext = React.createContext<WritePostProps>({
-  onSubmitForm: null,
-  isPosting: false,
-  squad: null,
-  post: null,
-  enableUpload: false,
-  formRef: null,
-  draft: {},
-  updateDraft: null,
-  formId: null,
-});
+// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+export const WritePostContext = React.createContext<WritePostProps>(null!);
 
 export const useWritePostContext = (): WritePostProps =>
   useContext(WritePostContext);
@@ -90,7 +81,7 @@ export const WritePostContextProvider = ({
             copy={{ right: 'Post' }}
             rightButtonProps={{ disabled: props.isPosting }}
             leftButtonProps={{ onClick: () => router.back() }}
-            form={formId}
+            form={formId ?? ''}
           >
             {component}
           </FormWrapper>
diff --git a/packages/shared/src/hooks/feed/useAdvancedSettings.ts b/packages/shared/src/hooks/feed/useAdvancedSettings.ts
index b2c1986161..9f4089bc8c 100644
--- a/packages/shared/src/hooks/feed/useAdvancedSettings.ts
+++ b/packages/shared/src/hooks/feed/useAdvancedSettings.ts
@@ -10,7 +10,7 @@ import useTagAndSource from '../useTagAndSource';
 import { Origin } from '../../lib/log';
 
 interface UseAdvancedSettings {
-  selectedSettings: Record<string, boolean>;
+  selectedSettings: Record<number, boolean>;
   onToggleSettings(id: number, state: boolean): void;
   onToggleSource(source: Source): void;
   onUpdateSettings(
@@ -30,11 +30,14 @@ export const useAdvancedSettings = (
 
   const selectedSettings = useMemo(
     () =>
-      feedSettings?.advancedSettings?.reduce((settingsMap, currentSettings) => {
-        const map = { ...settingsMap };
-        map[currentSettings.id] = currentSettings.enabled;
-        return map;
-      }, {}) || {},
+      feedSettings?.advancedSettings?.reduce<Record<number, boolean>>(
+        (settingsMap, currentSettings) => {
+          const map = { ...settingsMap };
+          map[currentSettings.id] = currentSettings.enabled;
+          return map;
+        },
+        {},
+      ) || {},
     [feedSettings?.advancedSettings],
   );
 
@@ -60,7 +63,7 @@ export const useAdvancedSettings = (
   // and currently used in simpler implementations of updating the settings
   const onToggleSettings = useCallback(
     (id: number, defaultEnabledState: boolean) => {
-      if (alerts?.filter && user) {
+      if (alerts.filter && user) {
         updateAlerts({ filter: false });
       }
 
@@ -68,7 +71,7 @@ export const useAdvancedSettings = (
 
       return onUpdateSettings([{ id, enabled }]);
     },
-    [alerts?.filter, selectedSettings, onUpdateSettings, updateAlerts, user],
+    [alerts.filter, selectedSettings, onUpdateSettings, updateAlerts, user],
   );
 
   const checkSourceBlocked = useCallback(