Munich was much worse. 3 lunch cafes, coffee shop, bar, and one of the beer gardens. Luckily I was warned and asked the places before I went.
Even the cab to the Munch airport would only accept cash. I had to walk across the airport to get it. His payment app was “not working”.
In Stuttgart it was only the smaller places. Although we made sure find places that took corporate Amex using a website.