@maxmp OK, you're onto something here, but this seems to work in the opposite way to your advice!
I had added the Music folder via "Add Folder or Storage" which results in my library comprising 30 folders and 238 songs all of which are MP3 files with no cue files showing, and no virtual folders.
If I remove my music folder, and enable the setting "File Access Legacy Mode", PA restarts, and now I have 86 folders and 2782 songs, and everything works as before.
If I disable legacy mode, the app restarts and I still have 86 folders and 2782 songs, but under Library>Folders Selection it looks like this:
But everything works as before.
Re-enabling "Mike's S22 Ultra" Music folder results in 30 folders and 238 songs.
Don't know if it helps, but I've had the S22 since April and transferred apps and settings from my old S10+ using Samsung Switch. Could this allow the legacy settings/database with cue folders to work? It was only after I did a Library>Full Rescan that CUE folders disappeared.
Thanks for your help,
Mike