OBD2 diagnostic data and telematics are different subjects

In most legacy manufacturers (e.g, not Tesla) vehicles you can disable/remove the communication module, which is a cell phone modem that interfaces with the car.

For Toyota specifically this is called the DCM (data communication module). It’s a little black box. In Fords/Hondas it’s called a TCU (telematics control module).

In some cases, you can just pull the fuse for the telematics box.

In general, when you research whether you can physically remove this tracking stuff from modern cars, the key word is to use is “telematics”.

I’m afraid it’s going to get much worse. Right now you can at least disable/take out the little box out of most cars without losing functionality for the most part. Soon it’ll be crippling to do so.

What’s worse is that in the EU, the connectivity is mandated with eCall, which calls the police with your coordinates in the event of a crash.

Though the EU has strong data privacy so at least you can be semi confident you can opt out and have your data forgotten from the manufacturer

Don’t worry Honda has this telematics garbage too

https://mygarage.honda.com/s/hondalink-marketing

Most privacy conscious people don’t use iCloud, the only place where by default Apple has the key (can be changed for users that don’t want this)

Apple as of 16.2 has an option to fully encrypt iCloud backups without allowing Apple to have a key. Assuming this is what you’re talking about.

Otherwise, most privacy conscious people are not using iCloud.

If you have the Play Store then you have GApps on your phone, which does phone home.

It is a business risk for Apple to mine data on data they have explicitly confirmed in this ToS to be e2e encrypted and private.

If we’re going that far, none of the Broadcom/Qualcomm/Exynos/Snapdragon chips have open source firmware. Additionally google services are all closed source and proprietary.

Backdoors exist but all phones have backdoors in them and should be assumed they are exploited by state actors.

From a privacy standpoint, on stock mobile OS, Apple is the lead. I certainly won’t disagree that there are custom roms without google services that are superior though.

Generally Apple apps e2e encrypt your data and can not be read/mined by them. There are caveats such as Siri (anonymized voice clips uploaded for example) or (iirc) Apple News. Things like notes, fitness/health, or iMessage are your data.