The PeerTube federation is currently broken. It will either be backported or released in version 1.0.0: https://github.com/LemmyNet/lemmy/issues/5597

Piefed support Peertube. Some time video are missing but for most part it works well.

For now, you can only comment on peertube’s channel if there are some comment. I opened an issue about it. You can comment on PieFed community.

Here is an example : https://piefed.social/post/695735

Unfortunately I can almost never find these accounts from mastodon.