Last time I tried YouTube music, it was an underwhelming experience. I expected it to show only official videos, but it showed any random video with music. It substituted Google Play Music, where you could have a curated library and your own uploads, with random music videos.
I think it only show "any random video with music" if you've liked the video and it appears to be a legitimate music video (i.e. without dialog/non-musical noises etc.). I use YtM a lot and the only questionable videos are ones that I've hit like on (beat saber being a prime example - I've learned not to like anything like that, these days).
I can't say that I have experienced the random music videos thing, but I agree it does feel like a bit of a downgrade from Google Play Music. I used the podcast part of Google Play Music a lot, since it put music and podcasts all in the same spot. Now I have had to switch to pocketcasts for that instead.
