Yeah sadly that's the nature of it being decentralized, I guess.
But just FYI, from what I understand, if you write a comment in Mastodon, it is visible in peertube.... I think...? Not sure. So if you want to get rid of youtube, just start with watching Peertube whatever way you feel is best for you. I'd suggest Mastodon, its pretty simple and good looking way to do it.