Music Playlists disappeared upon reconnecting with Apple ID

Up until today Aug 19, 2023, my two iPads and my iMac synched perfectly when I added new songs or created a new playlist.

However, when I logged in today and opened Music to select a playlist, all 20+ playlists were gone!.

I immediately checked all my settings, then checked my iMac. Settings looked okay, all playlists are present on iMac. Then I checked my second iPad and at first the playlists were intact but as I was about to select one, they all disappeared! I must add that that iPad had not been used for a while, and when I logged in, an alert popped up that I needed to re-login to my Apple ID. I don't know why that would affect anything, but who knows?

Any suggestions for regaining use of playlists on the two iPads?

Thank you,

Tod