GPS not working (“drifting”) even after getting a new iPhone and resetting everything.

7 months ago the GPS on my iPhone 13 started “drifting” in all navigation apps. Basically the GPS thinks I’m half a mile back from where I came from. It gets way off when I make a turn. Restarting the phone, toggling between airplane mode, and resetting network settings did not fix it. I ended up upgrading to a new iPhone 15 Pro. To my surprise the issue continued with the new phone. After hours on the phone with Apple support I’ve tried updating to the new iOS via hardwire and the computer, completely erasing the phone and redownloading only essential apps. None of these solutions have worked. The GPS across all navigation apps is still unusable. I mostly use GPS in my 2021 Atlas with CarPlay. However I don’t think it’s vehicle related because the same issue happens in my wife’s 2013 Cruze with no CarPlay. Any ideas on what to try next?