Extremely confusing issue with Catalina

I have a perfectly working otherwise Catalina install:

i5-8600k

16GB 3000MHz

Vega 56

MSI Z370 SLI PLUS

System boots and works fine, sometimes for hours without issue.

I get a random black screen that I can't return from. Only option is hard reset.

Sleep is entirely disabled so it's not that.

It isn't a panic, and the machine doesn't turn off. Lights, fans, etc stay on and even my bluetooth speaker stays connected, but screen turns off completely and I can't get back in.

Sometimes it triggers by itself, but it seems like there is another way to make it happen

If I start to plug in a USB device that wasn't inserted at boot, the minute i even touch the I/O shield to try to get the USB cable into the port, my screen goes black. This makes me think it's a hardware issue, but the exact same thing works just fine on Windows. Any assistance would be appreciated.