This may help you guys.
I have had mine for a week. 2020 GMC 2500HD AT4 Duramax. I couldn’t figure out why between short key cycles I would lose all audio and everything in the IC screen expect for the main info page with speed and trip etc. nav, audio, phone all blank. Center stack screen shows me that the Sirius radio is on and the songs change but I have zero audio, no audio for Bluetooth or apple car play either. I tried key cycles, opening and closing door etc....
WELL....its apple car play. On these short key cycles I would leave my iPhone plugged into the USB port. Drop my kids off at school and come back out to no audio. Now when I have these quick trips I make sure I unplug my phone and everything functions like it should. It takes 3-5mins for it to reset with truck off and door opened if you do leave it plugged in and this happens to you. I let my dealer know of the issues I was having but plan to call them today and let them I know I figured it out. Clearly they wouldn’t of had these issues if I dropped it off to be looked at. Maybe this works for you. Good Luck