Chicago area... I have iPhone 12 Pro and have not seen the 5GUW icon despite being in an area with Ultra Wide service. My son has iPhone 13 and gets the 5GUW icon. Interestingly, we both ran SpeedTest app in same location at same time and speeds were the same for each of us despite my phone not showing the 5GUW icon: 460 down; 80 up. So, I think it is a software icon issue on the iPhone 12 Pro not showing the 5GUW icon.
Running 15.2.1 and my phone has eSIM. Anyone else with iPhone 12 or 12 Pro experiencing this anomaly?