Final (?) report on my HW3 update: Mobile service appeared at my house at the end of the estimated time (12:30pm) and work was completed just after 2pm. FW 2020.12.5 was loaded, while the map software reverted back to 2019.6 (was 2020.12; it's updating as I type). Phone had to be re-paired, along with signing in to my WiFi password and logging in with my Netflix credentials. Otherwise, everything else seems to be in place (trip odometers, profiles, radio favorites, etc.). Forgot to ask the tech how common it is now for mobile service to update vehicles.
After the tech left I took the car out to get the cameras calibrated. It required about 5 miles driving on city streets and a freeway before the ring around the steering wheel icon turned completely blue. NoA felt the same, with no noticeable ping-ponging within the lane. Properly paced the cars ahead of me and adjusted to the following distance changes I made. Automatic lane changes worked fine with the exception of the first one I tried when it took a little bit longer than "normal" (I'm on Mad Max). Turned on the visualization preview and signal lights appeared on the screen, along with the virtual limit lines at intersections. All-in-all a nice and easy upgrade. Tech left the car unblemished and as far as I can tell, the screen was cleaned.
Note: While I was charging the car at a supercharger I returned all of the items in the glovebox and center console back to where they lived. I plugged in the flash drives for my music and dashcam/sentry. I then drove to go pick up an Rx. When I returned to the car, the sentry activation screen was displayed (i.e., the big red eye on a black background) and it did NOT go away when I got in and selected reverse. In fact I was able to move both forward and backward and the screen did not change (to the rearview camera or map display). Put the car in Park and then reversed again and all was normal. Another, possibly related item: the top left side of the screen only showed a big D while I was driving; no speed or P R N D; they were there earlier on my drive. All other icons looked fine. When I got home I re-booted and the display returned to normal. Haven't taken the car back out yet but I'll keep an eye out for any other bugs.