If buying new, I believe you can ask to have the modem removed from the vehicle, which wouldn't allow your car to access the internet. Haven't had the opportunity to try this myself yet, but very much plan on it for whatever vehicle I purchase new in the future.
You really can't
Also don't start breaking your own car like some of these comments suggest. It can go wrong in many ways and may even harm the value of the car.
As long as you have a Google or Apple phone in your pocket... The car will actually not gather much more than your phone already does... So don't overthink it.
Privacy has become a very important issue in modern society, with companies and governments constantly abusing their power, more and more people are waking up to the importance of digital privacy.
In this community everyone is welcome to post links and discuss topics related to privacy.
much thanks to @gary_host_laptop for the logo design :)