I took a quick swing at that idea but found that when PieFed imports a new PeerTube video it doesn't put any special marker on it to identify it as a PeerTube video. So although I've added a post type filter to the search tool (check this out https://piefed.social/search - set the Type to 'Video and 'Sort by' to 'newest' ) the results you get are all mixed in with other video content.
Oh well.
Along the way I also found a tweak that suddenly makes the keyword search way better so that's a bonus.