https://www.digitaltrends.com/music/what-happens-to-google-play-music-youtube-music/

So basically... Everything you got on GPlay will go over there.
Unless I missed something. Look, all I care about is listening to my tunes and that's an end of it. I don't see why people are freaking out like China is invading. And hell, you can download Youtube music offline so no need to worry about your data plan.