Apple is cleaning up a bit and has removed all audiobooks from German Apple Music. Audiobooks are books that are read aloud. Audio plays, on the other hand, i.e. stories with sound effects and dialog, remain in Apple Music.
Audiobooks can now be found in the “Books” app. This is a bit more logical, but has a disadvantage for Apple Music subscribers: the audiobooks are no longer included in the subscription. In “Books”, all audiobooks have to be purchased separately, and there is also no subscription available.
As it seems, this decision lies solely with Apple and not with the representing publishers. They will continue to offer their audiobooks on other streaming services like Deezer or Spotify. So if you use audiobooks extensively, that might be reason enough to switch streaming providers. For Spotify, we have this app tip for convenient playback.