This is actually embarrassing. I really should know about this by now. I can't figure out how some apps are getting my country code. It's likely originating from automatic timezone detection over 5G. But given that my phone number isn't passed up the stack to any old app that asks for it (right?), then how are apps still getting the country code, given that it's one of several in the same timezone? I'm talking totally new install just saying "Hey what's your phone number? Let me help you. Here's the country code."
Hint: it sure as hell ain't from my IP address.
What am I (not) doing that's allowing this? Having a SIM?