We were in Aachen too a few years ago. Wanted to see Charlemagne’s throne (which was only open 11:15 to 11:45 or something obscene). We didn’t wait. It was totally inner-city, very Muslim-rich, at least where we stayed.
I was there in the 70s before all this Muslim crap. A lot nicer then. Wife was there in Germany a couple of months ago...she saw virtually nothing but Muslims in Wiesbaden.