Do wireless carriers install additional software onto the iPhones sold thru their stores?
Can a wireless service provider gain access to my iPhone remotley? (To change settings, view personal info, etc.?)
iPhone 13, iOS 17
They have their carrier settings they control. But as far as changing your settings or gaining info (they already have your personal identifying information or at least that of the account owner since it was needed to open an account) the answer is no. Your usage via the carrier system (numbers of calls made and received, etc) of course.