Guidelines
Feature Description
This is a feature that has been tracked on Signal for over 7 years with little to no official response from the devs.
This is a workable feature already on iMessage and WhatsApp, or so I gather
As far as best implementation, I probably prefer that the global setting prevails if in the DISABLED state, but when in the ENABLED state each coversation can have a toggle to disable it.
I'd be happy with any approach though.