Opting out of ATT seems like the most obvious no-brainer, but are there options for phone service that are actually halfway decent?
Or as an alternative, would it be feasible to get some kind of internet phone/texting service, use that over wifi, or maybe have a basic data plan to go with it at most?
Most carriers know your name, your internet usage metadata, and your location all the time using cell tower triangulation. There have been multiple reports of phone providers selling location data and sercurity breaches. If you have a phone that provides MAC address randomization and you use a VPN then I think using public WiFi is more private than having your mobile data turned on all the time.