I some months back called every independent EV mechanic I could find a listing for in my state to see if they would help me disable the cellular modem of any of the models I was interested in buying, and they mostly told me either that they couldn't or wouldn't. One of the more polite shops I got in touch with explained that many models don't have a separate board that can be disabled anymore, or otherwise have more things on the board that need to be talking on the CAN bus for other, actually important parts of the car to function. As such, I still have my old car.

Since then, I've learned about the 50ohm dummy antennas you can buy. I might try that if my car dies before an AWD/4WD Slate truck becomes an option, and also if my living situation can accommodate charging.