In most cars (don't know about tractors), the variety of computers that make up the whole are split into two major groups.

The first are what are deemed safety-critical. Stuff like the antilock brake system for example. While there is technically what might be called a computer, it's REALLY simple. Some might even say primitive. There is no operating system, the foundational code that runs it is just enough to do the job and NOTHING more. There are some other systems in cars that are this way; probably stability control systems and such. The other half is all the modern bullshit that is non-critical. The infotainment system, telemetry systems, things that interact with a manufacture's infrastructure for app-based car controls (remote start, unlocking, etc). That's the bullshit that is just there to make idiots feel better about themselves because they NEED Carplay. Now, if we just had a lovely segregation of these systems to the point where the bullshit was truly optional, you could just unplug it and go about your day. You don't want telemetry, unplug the box, car functions normally. The problem is that the manufacturers are greedy. They want more and more money so the integrate the non-essentials so deeply into the car that it will not function. It's not required, it is a choice on their behalf. They NEED that telemetry data to sell to data brokers because they won't be as profitable without it--they promised the shareholders growth so they make engineering decisions based on that greed. You unplug those systems, you might brick your car. Also, as noted, they're deeply proprietary. You can't just pull the gateway module and configure it to ignore missing components. No, you need a dealer to use their special software (and probalby hardware), each bit of software is cryptographically signed such that any modification will cause other systems to flag it as broken and everything grinds to a halt. If even the dealer wants to change something, they have to connect to a central manufacturer system, request the ability to make chnages or at least that the changes are all logged and tracked centrally. Manufacturers put all sorts of hurdles in place. Volvos lock eveyrone out of the system with some sort of PIN that only their software will generate to unlock configuration changes. They claim it is for out safety, but that's the same old bullshit. Modern cars and electroincs are bad not because they don't do amazing things, it's because those amazing things are all locked up behind a greedwall. Good luck if your shit breaks. Good luck if the manufactuers screws it up, that's also your problem.

I have a newish Volvo. There is a battery that provides backup to the telemetry system. I don't give two shits about that system, I'd love to rip it out. However, the car has a timer that, after 7 years will display a permanent error in the display saying that the Volvo On-Call system has faulted. I can replace the battery, in fact it is trivial. 15 minutes and it's all set. However, that timer will NOT be reset. You can't just do things like pull the battery cable, you need Volvo to go in and use their systems to unlock and then reset the timer. Cost: about $300. To turn off an error message. Remind me again why the fuck this is a thing?