Framasoft created an extra search engine for that, a instance can be found here: https://search.joinpeertube.org/

I'm not using in much but it queries several servers so it might be what your looking for

I've had good luck by using https://peertube-search.com/ but beware, use an ad blocker because it's pretty loaded with spammy ads. However, if you do that you can actually filter by language, category, upload date etc. Everything that should actually be available in the official search https://joinpeertube.org/browse-content

I'd also like to know this

I wrote this a few years back, which includes some processes I used when trying to find stuff: https://deadsuperhero.com/...

Content discovery is still kind of an unsolved problem for things like federated video. I've played around with this a lot, but it's almost like we need people actively recommending stuff in a quasi-centralized way to help us find things worth watching.

There's a Lemmy community for PeerTube that might be a good place for content recs.