Roaming still a mess in Europe?

I just came back from a 1,200 km trip across three countries and I’m honestly fed up with charging roaming. Every network has its own app, some require a credit card pre-authorisation, others only accept their own RFID card. The price per kWh varied wildly for the same type of charger depending on which app I used. Why can’t we just have one standard like they do with petrol stations? Has anyone found a decent aggregator that actually works across borders? Also, am I missing something with the new EU rules on transparency? I feel like I’m still getting surprise fees posted to my account weeks later.