After trying a different SIM, doing a factory reset, and going through the other troubleshooting steps, either there's been some kind of hardware fault, or something about the signal being sent/configured on my phone.
I cannot seem to get service to one of the two Pixel 3a XL phones owned, even stating 'No Sim card' on the lockscreen.
Pack1, we would be happy to help with getting this checked out to see what is going on with the phone connection. Please send us a Private Note for better assistance. JoseL_VZW