I have both a new electric Audi and new Tesla. In either car I can just remove the sim and it'll completely disable all of the internet based features. A lot of the FUD around new cars is spread by grumpy old automotive journalists.
As far as I know yes you can still supercharge. The only thing I lose is the ability to remote control the car when out of bluetooth range as well as all the map & streaming features.
Wait until they put in eSIMs. Those you can probably disable as well but with a different level of expertise. Or you can damage the antenna or just stick aluminium foil tape onto it.
If you were to remove the sim card, would that void your warranty with either of those manufacturers? If so, that is not a long term solution, unfortunately.
No. They just stop calling home to the mothership. My Audi actually had a faulty sim module for a few months until I had time to get it fixed and other than not being able to check the charge status while away from the car it didn't really bother me.
