LTTP but just went through this with my 5800X3D and it was a bad CPU…This is the board I used to build my 5950X system with and it was never stable. To the point that the system was completely unusable due to random power-offs that ended up killing my installation of Windows...
I wasn't able to troubleshoot it properly due to lack of available time to waste, so I just drained the coolant and disassembled it.
When I got time about 10 days ago, I installed an air-cooled 5800X and air cooled video card and used different RAM and reloaded Win 10. It's been rock-solid since so the processor, video card, or RAM seems to be the culprit.
Bought the Dark Hero as part of troubleshooting and now don’t wanna swap back to my cheap B450.