I just updated my Pixel 3 phone to the new Android 10. As of last night, my phone displays "Preferred system" at the top where it used to say "Verizon Wireless" and there is a "R" next to the signal strength indicator. Based on the thread at https://support.google.com/pixelphone/thread/15864710?hl=en, numerous other users are now encountering this issue, and we are spread out across the country so it's not just my phone that is having this problem.
Workarounds in that thread include trying a factory reset or obtaining a new SIM card. Is there a suggested path forward here?