theoretically you should be right but there’s software hidden in the hardware that you can’t uninstall or modify that could (hypothetically) be surveilling you. like in the networking equipment that’s inside the phone.

realistically, i think the chances for that happening are actually very low, also because the networking firmware could only see your encrypted data packets, but it could still figure out the IP addresses that you communicate with. i’d rate it a none/low risk level.