Hi Peter, welcome to Cake! 😁 What an awesome first post.
From line 1 of your post I thought "Ugh, it's way past time for me to focus on figuring this out. I know I should be using Spotify but for some reason I'm the only person on earth stuck on using YouTube Music because...I don't know, somehow I got comfortable with it."
I pay for Apple and Amazon Music subscriptions, but rarely use them. I helped my wife make a list on Apple Music and when I ask Alexa to play something she obliges with a version from Amazon Music. My Spotify and Pandora trials of long ago never really converted to a paying subscription, even though I always hear Spotify is The One and I have a nagging feeling I need to revisit it.
I simply settled into YouTube Music and didn't know why. The My Endless Playlist is where I default 98% of the time and it just keeps getting better, I guess because when I do things like skipping songs, it guesses correctly that I've heard that one enough, let's move on.
Since I like to run and bike, one of my favorite features is the way it creates an offline playlist for me that I like that I never had to think about. If there's a song I don't like, I double-tap my Airpods to skip it and chances are it won't appear in my offline playlist anymore.
I have a vague notion that YT Music throws in performances from unknown artists, maybe just someone in their home. I think wait, a pro service like Spotify wouldn't do this, who am I listening to and why? But the thing is I usually like it so it stays and I keep wondering who I'm listening to.
For example, I like the song Rockabye by Clean Bandit. YouTube threw a version in from Madilyn Bailey. Who? The strange thing is it stays in my playlist because I like it. I had no idea who she was until I asked Wikipedia for this post.