WARNING: If you are running Android 12 Beta 4,
DO NOT not clear the MusicBee Wifi Sync app's data or you will lock yourself out of using it. The app will ask you to select the root folder of your SD card in order to sync, but Android will prevent you due to a
'"Can't use this folder: To protect your privacy, choose another folder" message. If you try to grant access to a subfolder, the MusicBee app will then tell you that you can't use a subfolder. As long as you set up wifi sync before Beta 4, you will be fine.
Here are some screenshots:
https://imgur.com/a/Uh9ttZ5.
Right before posting this comment, I stumbled upon
this Reddit post where someone is having the exact same issue, but with a different app, so it seems something changed in Beta 4.
The user created an request in Google's issue tracker, so please consider starring it so they will hopefully revert the change: https://issuetracker.google.com/issues/196422354. Thank you in advance.