If you have the MS Store or Game Pass version of the game, there’s a way you can repair the game from within Windows. I don’t know exactly where it is since I have the Steam version. Perhaps someone else can point you out to where.
Seriously, MSFS is looking for a file it can’t find and sh!&ting the bed as a result. You should be able to repair this easily if you have the MS version. It’s unlikely it has to do with the community folder. If it can’t find something there, it ignores the mod. This is an issue with the core sim files.
Unfortunately, I have no idea what you could do if it’s the Steam version