Vanished playlists in upgrade from iTunes to Music!
I held off from the upgrade from iTunes to Apple Music for a long time, then in one jump went from Catalina to Monterey. When I opened Music for the first time, my library still contained all my songs, but all the playlists I'd made had vanished from the left margin (years of work!). I've scoured the online message-boards, but no solution seems to apply to my specific problem (including using iTunes, which Monterey isn't compatible with). How do I restore my vanished playlists?
MacBook Pro 15″, macOS 12.1