I’ve got a 2020 LT Trail Boss with only 6000 miles on it. Same issues here with screen being black, but at start up the truck would not start and stated it was in battery saving mode. Just saw where GM has a recall for 19-20 model trucks due to battery connections being faulty.
https://www.consumerreports.org/car-recalls-defects/gm-recalls-full-sized-pickup-trucks-due-to-battery-connector-problems/