Here in Dresden - where "conservative" can sometimes feel like a charitable understatement - it's pretty mixed, based on my observations, I'd probably estimate about 50/50 card vs cash, at least in the supermarket, with a smattering of people using phones or something fancier. There's also a lot more self checkouts in supermarkets now, and most people who use self checkouts tend to also use card in my experience.

Here in Cologne I see most people paying with debit cards, with the exception of very old people.

Cologne is also a bit bigger, out in the smaller towns around Cologne they still pay with cash most of the time. But last year I did notice an increase of card payment at the supermarket. At the local baker and butchers you can forget about it though, they don't even have a terminal for it.