After giving it some thoughts I decided to mix german and english posts here from now on. I am still not really happy with the solution but I don’t see a better one. I will try to use the „German“ and „English“ categories properly so you could subscribe to one of the english-only or german-only RSS feed if you want to keep it separate.
In the coming days, I am going through my recent posts and will get rid of the „General“ category in favour of properly moving them to the English category. A „General“ category does not seem to be very useful anyway. I should use tags anyway, damn. Will do. Will do.