Correct me if I'm wrong:
Like a "Smart" TV you can just not connect the car to the internet and ignore all the features requiring a SIM card or phone connection.
I'll just use a phone mount and ignore the infotainment shit entirely besides offline features if it comes to that.
I'll pull the dashboard apart and wire in a dumb radio/mount it somewhere.
I'd even find and destroy the antennas if I have to. I'll buy 3rd party ECU if I can't. Exhaust all options.
I can drive old cars too but eventually that gets unrealistic and hard to maintain.