Google Play Music was legitimately excellent. The last Google service I ever paid for that I was 100% happy with.
It died because that style of music app wasn’t seen as “in vogue” anymore. It was much more akin to a music manager app, but also one that allowed you to manage things on the streaming service. Best of both worlds. Library management tools and options that have been a thing since iTunes popularized them a decade earlier, but all the content, suggestions, playlists, and radio functionality of Spotify.
And someone at Google decided to burn it down, make it a Spotify clone (with all the same neutered management tools), shove it into YouTube, and gave a huge middle finger to customers that paid for the app as it was (and they probably got a promotion for it).
Don’t ever trust Google. Doesn’t matter if it’s a good or bad service, it means nothing. They’ll fuck it up eventually.