Update on the blank screen phone:

I decided to charge the phone (which had died) and try AirDroid. I had set this up previously on my phone as part of a demonstration on video calling. (I needed to display my phone screen on a computer monitor.) Unfortunately, this didn't work because apparently AirDroid didn't start up by default on my phone.

Then I shook my phone and the camera activated. (One of the nice features of the Moto phones.) I couldn't see anything, but I felt the tell-tale vibration that meant "launched the camera app." I tried taking some photo using the volume keys and taking screenshots. Lo and behold, those appeared on my new phone in Google Photos.

So the phone is still working - well, except for the screen.

My next attempt will involve my son's Nintendo Switch base. The Switch uses a USB-C connector just like my phone. It connects from the Switch to an HDMI port. If I can get this to work right, I might be able to see on my TV what I should be seeing on my phone. Then, a Bluetooth keyboard might help me interact with the phone itself.