YouTube music doesn’t seem to care much about where the music comes from. They do have formal album libraries but not everything is carefully sourced and labelled like Spotify. That’s what makes it good, because you can find tons of lost mixes, old unreleased track and vinyl rips, leaks of new stuff from current artists

I use YouTube proper quite heavily and I find it pretty easy to spot the AI stuff. At a minimum there’s usually a comment pointing it out, just like Instagram videos