Of course, a disconnected phone loses a lot of its core functionality, unlike a car.
On some cars, there may be a fuse for the telematics. For example, on GM cars, the fuse diagram may list one of the fuses as being for OnStar. Remove that fuse if you want to disable the OnStar.
You can also try to find the antenna and cover it with radio-blocking material.
Telematics is common these days, and nothing about it is specific to electric vehicles. So it is not a reason to choose or avoid an electric vehicle versus any other new vehicle.