Good news for all EV drivers! Tesla opens many Supercharger also for Non-Tesla-Cars. Starting on June 21, 2022 Elon Musk allows everyone to charge at his Tesla Supercharger. Of course not for free. The prize 0,71€ per kwh is rather high, but compared to 0,79€ at the Ionity charging stations it is still cheaper.
You just need to open up your self a Tesla Account at the Tesla App and be able to charge. The map in the app shows you all available superchargers for Non-Tesla-Drivers. Please see the screenshot of my Tesla App.
https://apps.apple.com/us/app/tesla
https://play.google.com/store/apps/details?id=com.teslamotors.tesla&hl=en&gl=US