Your best bet is to find a car where its easiest to disable the antenna/cellular modem for, so look for a car that has a fuse for the DCM(digital communications module) you can pull, as having it be a fuse means you can readily reconnect it should you need to, try to find its schematic online, or find the repair manual for the car or use a car maintenance program,

Apparently its also possible to call the car company and ask for an opt out when serviced,

I vaguely remember some people experimenting with replacing the head unit with aftermarket ones, but no idea how well that would actually go in practice