In a lot of cars its the infotainment system. In my car there is an information system that runs in tandem with the stereo and feeds information to the dashboard. Pull that out and it cannot communicate to the manufacturer. However pull that out and your stereo no longer works. There are after market stereos but nothing that fits nicely in your dashboard AND has a usable UI (there exist tesla-style giant LCD screens but the software is what you would expect from an unlicensed chinese manufacturer)

Wait 5-10 years for the telemetry systems they rely on to go obsolete.

In the US at least, you can look up the fccid: https://www.fcc.gov/oet/ea/fccid

In a lot of cars, this will be an identical board (since the manufacturer only wants to certify one vs many of them). This gives you at least a start of what to look for.

If sure that would void the warranty or some other consumer punishment.

I wish there was a law that products which data mine had to be free and it was illegal for paid products to do it.