I loved Google play music as a locker for my owned music and a a storefront to buy what I wanted. YouTube Music made me abandon it completely and move my owned music onto my plex server.
Why does Google have to ruin everything? Still bitter about Google Reader closing back in the day. That was the beginning of the end of me having confidence in their services and moving to self hosting as much as I can.
Google Music was the only place I bought music digitally other than iTunes, and I used it religiously. I downloaded all of my personal music uploaded to Google Music before it closed with the intention of running my own Plex server. A friend who works IT security scared me into not running an externally-accessible Plex server.
So I fight with the YouTube Music app being complete dogshit on CarPlay. If you think the app is bad on mobile, just try the CarPlay version. Unusable.