While Apple Music is annoying to use, the Spotify app is even worse for me. Audio quality is also markedly worse — I have verified my hunch with a double-blind side-by-side test. Spotify is now way too expensive for what they offer and the only noteworthy integration they offer is Sonos.
I'm entirely with you that even if I was a Spotify subscriber, I don't want their podcasts and audiobooks. In separate apps, optimized for use-case, covered by the same subscription, maybe. Forcing all those fundamentally different media formats through one UI and funnel is just wrong.