Came up to my studio this morning and my 2013 Mac Pro wouldn't start. I had started a Time Machine backup when I left last night and hadn't touched it since (I am running manual TM backups only, since scheduled backups mess with DP for me).
Tried to press and hold the power button… nothing. Unplugged the power cord and plugged it in again... started right up. So I ran a session and then set it to run the Montery and Safari updates while I went to lunch.
Come back from lunch… dead again. Unpluged power and plugged back in… nothing. Unplugged and left for 10 min… still nothing. Unplugged everything from the back of it and just plugged in my USB keyboard and display port monitor (and plugged the power cord into a different outlet). Still nothing. The little lights on the back panel that outline the USB and TB jacks light up, which tells me it's getting juice.
If I can't get it to boot, I can't even get into Recovery mode to try to run Disk Utility. I'm on hold with Apple Support now. My nearest Apple Store is a 5 hour drive from where I live.

Anyone have a suggestion on how I could bring this back to life? (Defibrillator?)