I have a 2nd-gen iPad, which just automatically updated iOS to 15.8 last night. When I tried to play my Apple Music Playlists in my car (no WiFi connection, Bluetooth to an FM radio adaptor), Music exhibited the same dysfunctional symptoms as described by most other posters in this thread: Music hangs for at least several minutes (or perpetually) at startup; plays anywhere from part of one song to several songs, before completely hanging up, and not playing any more songs until I reboot the iPad. I rebooted the iPad multiple times (and after one reboot, all my playlists completely disappeared from the iPad; Playlists reappeared after I signed back into Apple Music with my Apple ID, separately from signing back into the iPad with my Apple ID, AND after I then rebooted the iPad once more), and I tried signing out of my Apple login, and then signing back in again using App Store (since trying to sign in through the Settings app almost never works). On several occasions, Music displayed an error message to the effect that Music refused to play any of the songs stored on the iPad because the iPad was offline. Well, yes, it is offline when I am driving in my car, and that is the reason I pay $11/mo for Apple Music, so that I can play my downloaded music while I am driving in my 20-year-old car that does not have Apple's automobile client installed. I do not have an iPhone, and my iPad does not have a cell connection, and neither of these connections would be adequate to keep me online while I am driving between cities on a CA interstate highway. Plus, until the iOS automatic update last night, I had successfully played all of the songs in my Playlist sequentially for hours on end while driving with no Internet connection to the iPad whatsoever. It seems clear to me that the update broke the formerly happy configuration (or actual software).
And, yes, I know that my iPad is beyond the 5-year support period for its iOS, and that is probably why 15.8 is the latest iOS that Apple will install on my iPad. However, given that prior to installation of 15.8, Music ran as advertised and as expected on my iPad, I think I am justified in protesting Apple's decision to apply a demonstrably defective update to my iPad. I have now turned off auto updates on the iPad, since it seems like I shouldn't be getting any more at all, according to Apple's update policies.