Google Play Music worked perfectly well for me, and I used it as a Spotify alternative, not even for the music library features.
The switch to YouTube Music has been terrible.
Dead simple things don't work: my son would listen to a specific white noise track at night over his Google Home Mini.
Previously, we could tell it to play the song, then say "repeat on" and it would repeat indefinitely until he woke up and turned it off.
YouTube Music simply doesn't work repeating over a speaker.
What's even more maddening: I can repeat a song indefinitely on the Android app, but once I cast to the Mini, THE OPTION TO LOOP IS CANCELLED AND DISAPPEARS.
The only solution: I had to make a playlist that plays the same song for hours.
From what I've read, it seems to me like this shift to YouTube Music is primarily a licensing issue. Rather than pay for streaming rights to music tracks, Google seems to be using the library of music it has on YouTube to retroactively backdoor a streaming service that plays the YouTube videos without the video.
I suspect the repeat restrictions are a side-effect of this, somehow.
I would switch to Spotify (and may still do so) but I'd still be held hostage to pay YouTube the same price to run without ads (the primary reason I bought the package in the first place), so my choice is to switch to Spotify and make my kids watch YouTube ads, or pay double.
RIP Google Music indeed