First the crappy new UI, then they impose a Community tab beta on me, making my Discussions tab content inaccessible, and now I realized that Youtube combined some intelligent algorithm with total stupidity.
I had assumed that automatic captions are crap. Seems they work quite well though and the crap is what happens when the wrong language is set. So apparently the speech-to-text logic is quite good, but for some reason it does not detect the frickin' language everything is spoken in. So I realized all my vids got auto-generated subtitles, a failed attempt to interpret English spoken word as German.
So I went through all my videos with spoken content and set the video language from undefined to English. First attempts didn't immediately yield results, but I assumed it takes a while before it re-scans the contents. Apparently you can't trigger it manually.
So I just uploaded a new video (and my vids are not optimized for streaming, i.e. they likely can only be processed once the upload is finished) and on the very beginning of the upload I set video language to English. ... And when the video was finished, it had again added German subtitles.
I have now set my channel location to USA, hoping that might convince it. But I shouldn't have to.
This is the constant fail and facepalm that keeps convincing me not to go into a deeper business relationship with Youtube.