My music is working again but only after hooking back to my Mac, setting it to sync no music to remove any sign of it from my onboard library, then reloading all of my playlists onto the phone once it had been emptied out.
until then the only tracks that would play were, primarily, tracks bought off iTunes, with a handful of non-iTunes purchased songs, though **** of if I know what they had in common.
it went through two different stages as well this time for my collection disappearing prior to deliberately removing everything and reloading it onto the device:
1) not being present on the device at all, including all of my playlists disappearing after this morning’s sync where I tried to add ONE song from my Mac Apple Music library to the phone, leaving nothing but my iTunes purchases.
2) a second sync attempt that failed to load most of the missing music, ASIDE from the one new song and a handful of others, but somehow iOS Apple Music now displayed all the missing tracks and their relevant playlists again, but any attempt to play them would prompt a “not available in your region” error.
which again makes me think there’s a database corruption of some kind that is making it think in iOS 18 that music tracks which aren’t associated as being iTunes purchases under your Apple ID are, somehow, region locked DRMed songs? Even if these are songs you’ve ripped from your *own physical collection*
utterly bizarre and worrisome that at an OS level there can be this kind of lockout of our own local files; even other music apps that use the onboard storage library didn’t have permission to play them.
again: all on an iPhone 12 Pro running the latest public build of iOS 18