This isn't an issue with you, but a relation to another git. I come seeking discussion.

[SolarVampire]

I'm getting this error
I do not have a user named jjangli on my device, and yes I double checked for a hidden folder.
What is https://github.com/LaughingLeader/BG3ModManager using your git for? I'm not experienced. Yes I am going to dig through it myself as well, but I'm curious as to why this error occured, and hasn't yet. Meanwhile I also had a problem with it attempting to access C:\WINDOWS\System32. I ended up building a script to monitor all accessed files from the running process.
The list touched on the fonts folder, System32 en or something. Etc. I've since removed the process. But since it definitely had access to that folder at some point.. I come for discussion. I'm nackered that this error hadn't shown up before.

[SolarVampire]

Ok, so I've determined then it is someone who contributes in this community, so I guess I AM in the right place.

[CZEMacLeod]

@SolarVampire The paths including jjangli refer to the location of the source files used when the tool was built. They are not on your machine.
As for what the mod manager uses this package for - it seems to do most of its disk IO using this package, probably because it handles long file names / deep directory paths better, which is something that may apply to games when they are installed by steam or in some subfolder on another drive.
The specific error seems to be that it can't write the selected settings to Data\settings.json which is probably relative to the location of the executable. Maybe you are running it somewhere that is readonly, or you may have launched 2 copied of the app and it has the file locked.
Whichever way - the issue is not with this repo, but the consumer of the package, and you already know the repo location for that.