Where Europe dropped the ball is not forcing gas station like behaviour onto the chargers. Now we have a bazillion different charging cards and prices differ wildly depending on the Tarif.
https://www.fleeteurope.com/en/new-energies/europe/article/f...
So you won't have to sign up for anything else.
But there are also services like ChargePoint which unify the payment systems for numerous networks (certainly including Eon and Shell).