Apple Music playlist songs unplayable after iCloud overwrite

On Saturday I experienced that my playlist that I have curated for over 8 years, all of a sudden contained only 3 tracks.

No matter Time Machine backup would get the original playlist back, seems like something in iCloud was simply overwriting it as soon as the backup was in place.

I managed to get a full export of the playlist by using a Time Machine backup: turning off wifi after the backup was complete, and select the backup library by holding opt and launching Apple Music, and then the playlist is visible and exportable, until wifi is enabled and it is overwritten and contains 3 songs.

However when I import the backup, only about 20 songs can be played. The rest are indefinitely stuck in either Cloud waiting or error, and I cannot for the life of me figure out why or how.

I think I have updated cloud library and/or genius at least 100 times on several devices, deleted Genius.itdb and Library.musicdb, but the playlist is still stuck.

If I search for one of the songs on Apple Music I can stream it just fine, but if I duplicate it to the playlist it is greyed out.

The same thing happens in Apple Music web browser and on my Windows PC at work with Itunes: Songs are greyed out and can't be played (but streams just fine if I search for the same song in Apple Music).

As I can't find any logs or debugging related to Apple Music, how can I troubleshoot this?