Or with Tesla leave your card in your wallet, you won't need it. The station IDs the car and charges the card on file in your account. No card, no scan, no tap, no need to use an app, just plug in. At least in the US. Hopefully they aren't forcing this step backwards to contactless payment by card on Teslas too when the existing system is so much better.
Yes, but currently that's always the most expensive option.
I am driving a lot from Cologne to Bremerhaven. Depending on the spot where I stop, I would need an EWE, EnBW, Aral, ionity, eon, shell or some smaller card to get somewhat reasonable prices. Annoying.
Get yourself a Tesla account. I think all of the Tesla chargers between Cologne and Bremerhaven are open to any CCS compatible car; you just need the tesla app and register your credit card. Tesla is usually cheaper as well as more reliable.
But there are also services like ChargePoint which unify the payment systems for numerous networks (certainly including Eon and Shell).