At least from my understanding (specifically for Navidrome here), there’s no way to differentiate which user owns which track/album if they’re in the same location. Navidrome’s multilibrary configuration is basically just telling it “hey this folder is this library, that folder is that library”. A combined single folder is perfectly fine if users are fine with that, but in my use case my wife and I have dramatically different tastes so it makes more sense to separate it all out.