Fixed??? (Maybe)
So, after multiple times in and out of the shop.... they did a global reset on the system, they replaced the USB port, etc. This last time they replaced the "serial data gateway module" and fixed some terminal that had a bad connection. So far, after a month it seems to have fixed the issue (fingers crossed). I'm posting the invoice so that others might be able to learn something from it. I'll update if I get a blank screen again... I have a long road trip coming up so that should be a good opportunity to test it thoroughly.
UPDATE: Well, unfortunately have to report that after 5 weeks of hoping that all is good, I had another incident of the screen going blank again. I'm not driving much these days because I'm working from home due to COVID, otherwise it might have happened sooner. It was just a very brief outage. Screen went black for maybe 10-15 seconds and then came back on. It happened while I was in a turn lane and when it happened I noticed a slight hiccup in the rhythm of the clicking sound from the turn signal at the moment it went blank, which leads me to believe that it might be related to a larger electrical issue (although I have no automotive electrical experience.. just guessing). I have just under 10K miles on the truck now.