https://fedi-search.com/ which just adds the site parameters for different popular instances for the major search engines is probably the closest we have.
Marginalia.nu at least indexes the small web, but to my knowledge doesn’t really index the fedi yet.
The web instances work pretty well, that’s a shame the iOS app didn’t work for you. I’m only a consumer not a producer of video content so I interact with a fedi microblogging platform instead of having an account on a peertube platform itself. The Android app seemed okay but following users with RSS and interacting via my microblogging account, as well as directly checking my favorite platforms’ sites occasionally for serendipity seems to work the best for me.
I’m sure with the fundraising blitz the apps will get better too this year.
Meanwhile https://joinloops.org/ and https://joinpeertube.org/ keep getting better and better
Hopefully more creators will take notice and at least crosspost their content on better platforms too.
Looks like its showing in the DDG results for me this evening.