I am from the area where this particular sign with the strange track distribution is located, but I just can't put my finger on it. Dortmund, Essen, Cologne. Must be somewhere here because I've seen it so many times! And you're right, "Zentrum" and "Nordstadt" are pretty generic, that's why I cannot find it through online searches, I guess.

This looks so familiar, but where is it? Dortmund Hbf?

The official ProtonVPN app on Linux has a lot of problems, like a memory leak that exists since years now. At least for me, only the cli without graphical interface works (but does so very well after some tinkering). The lack of Linux support (especially no Linux app for the drive) has frustrated me to the point I am regularly questioning my Unlimited subscription. But I agree in general, you can get around a lot of the Linux limitations by using browser extensions like the ProtonVPN one. And overall the addition of new services and great security outweighs the lack of Linux support.