Using those biometrics to access anything without a warrant is legal and not protected by the 4th or 5th amendments.

Most states do not have any laws which restrict how biometrics are used. So using your fingerprint, face, or iris to checkout at the store doesn’t have any protections that would prevent that biometric data from being sent somewhere else, including the police. A store could gather facial or even iris data from a camera and you would have no idea because they don’t have to tell you.

Worse is that most people don’t see the problem with the digital panopticon because “they haven’t done anything wrong” and they are willing to give up their data for the idea of a theoretical safety.

Your face is not private, nor are your fingerprints. In public and in many private properties that are open to the public(e.g. stores) you have no expectation of privacy so you can be filmed within the law. You consent to facial recognition by passive agreement when you enter the public without your face covered.

Facial recognition technology is everywhere and there is nothing that will be done to curb it’s use.

Edit: To be clear, I do not support anyone or any entity using biometric data for any purpose except verification of identity for security purposes with intentional consent. Businesses or government using biometric data, or any data obtained without clear and willful consent, is unacceptable.

There is a software opt-out in the settings, but how effective that is may be questionable.

To be certain, you can disconnect the antenna that is used for cellular connectivity. How to do that will differ model to model and you would need to reference a factory service manual.

To be very certain, you need to disconnect power to the module with the cellular interface, which may mean switching to an aftermarket head unit(stereo) if the cellular unit is integrated with the infotainment. That can be as simple as removing a fuse or it may mean getting access to the module and removing and isolating the power wire from the connector of the module is separate from the infotainment.

3G was ended in 2022, which opens up a lot of models. I think 4g started being implemented around 2014.

The car would likely inform the owner to visit a service center and disable features that rely on network connection, but would not disable the car. The warning would be crying wolf, so a warning of actual concern may be ignored as part of the known connectivity error; which may lead to bigger problems.

Google your name. There are a bunch of websites that will list your known addresses, affiliates(family or people you have lived with), phone numbers, social media, etc.

That data is collected through various means and then are sold to interested parties.

The school you went to will have them on file. Otherwise, there are websites that you can order or view them.