Depends on in what way you’re looking for a youtube alternative!
I think peertube might be fine if you’re looking for a way to host your own videos, but it’s propably not a good place to just browse for video content the way you might with youtube. I think the most solid alternative for that is Nebula. It costs like a dollar a month IIRC and has a couple big name video easayist kind of types. It doesn’t really have anything to do with the fediverse or anything, but a majority of it is owned by the creators and from what I understand it is more generous per view than youtube, plus it has a buissiness model that doesn’t rely on serving you adds and selling your data.
Imo part of the problem with mastodon, at least in my experience, is that it’s sold as a twitter replacement while still being devoloped and largely populated by people who don’t like twitter (because it’s too “toxic”). This means that you can’t really have the twitter experience on mastodon by design so people coming from twitter mostly wanting to get away from musk bounce of. Bluesky has been a more successfull twitter replacement and I think that’s largely because it basically is twitter with feeds.
I think that mastodon should either commit to being more like twitter (which it is propably too late for at this point since I don’t imagine that their current userbase would be into that) or people should stop trying to make it the new twitter and instead let it be it’s own kind of different thing.