Hallo mein Freud,
I have several games, and some of them are fully translated into Spanish. The available languages are even reflected in the thumbnails. I am learning German, my mother was German and I have citizenship rights through descent. I would gladly translate my games into my mother tongue as well.
The problem I see is that translation can be very tedious in many engines. On top of that, German UI text does not take up the same space as English, so you have to adjust the UI and UX. And to make things even more complicated, the main language on itch is English.
To top it all off, without even promoting myself hahaha, I am working on a game about Germany, the second one I have made. In this one, the dialogues are originally in German and then translated into English. I am sure there are more like this out there, but you cannot find them.