Anime on Netflix on Netflix that doesn't exist?

So, a few days ago it happened again that I wanted to watch an anime further on Netlifx, but then this anime was in English subtitles and in Japanese, although there's also German and then there would be that some anime are gone and there are many who have never actually seen! So what should I do? How can I fix the error? The last time it was somehow gone after 2 days, but now it's still there.

You set it in the settings, if it is not available, then there's no German synchro.
Anime are removed from the range because the license has expired, so there's nothing you can do about it, try it on other sites.

Yes, I had the problem before and there are a few animes gone, but also a few completely random others

This is because Netflix is looking for "favorites" for you. But that's not just what Netflix does, but generally every page on the Internet.

Yes, that is yes, these series that are being proposed to me, I think, are only available in American Netflix, because they all only have English subtitles or English

My guess is that for whatever reason, Netflix switched to American servers

This can't be because there's a different directive in the EU than in America. The servers can't be changed so easily, especially because you are / are on the ground of the EU, etc.
There's some other reason, just delete the history, then a lot should happen.

So today I found out that my stepfather changed the VPN to wisconsin to watch series that are not available in Germany!

That is also an option, of course. But at least you don't know the reason.