Lemmy and PeerTube hasn't worked for a few months now - you'll have to fetch the vids manually if you want 'em.
There nothing wrong from PT's end - they fed with PieFed (e.g. the Linux experiment channel is here assuming your UI doesn't redirect you), MBIN (I believe), and Mastodon, but some change in Lemmy broke something.
Old post about it: https://lemmy.ml/post/15180175