> The average person has no idea what lineageOS is

The beauty of it is that the average person can buy a LineageOS-enabled system without having to know it's not "normal Android". Look at /e/OS for instance, and hopefully soon GrapheneOS will come preinstalled on some Motorolas.

And AT&T shouldn't allow you to connect other phones, or modems at all. You should only be able to get a phone by renting it monthly from AT&T - everything else should be illegal.

Personally I did none of that on my android (except set up firefox with ublock), and I get very few ads and they're easily stopped.