> Germans by-and-large even refuse to use debit cards (pin&chip)
I’d call that a minority, especially since Covid.
> not being able to pay with my card in a restaurant for example
An even smaller minority, especially for restaurants, slightly larger for non-chain fast food places that probably also cheat on taxes.
I don’t carry cash with me and pay almost everything with my MC debit or AMEX credit card, even in cases I can’t do that, I’d be able to pay with girocard (non-MC/Visa debit card, a widespread local system) if I had one.