EDIT: Yupp, I was just a bit impatient, took a few days but they are indexed properly now. I was confused because other videos that were just hours old were already in the index - but that didn't mean that mine were skipped of course.
So, I've started migrating my old YT content to a Peertube profile on peertube.wtf, you can find it here: https://peertube.wtf/a/wxnzxn
It's not any kind of high-stakes content, mostly old German YouTube Poops from the early 2010s when I was a different person. So I am not all that disappointed that I can't find my own content - but I am confused as to why it doesn't show up.
When I check https://sepiasearch.org/ and look at the instances in their index, Peertube.wtf shows up as available and in the index
But trying to find any of my videos returns no results, even for my amateur game trailer I uploaded days ago - so I doubt it's because of some kind "just wait a bit longer" issue.
Is there something missing? Could it be, that the instance has been (shadow)banned and removed from the index?