Still no solution, I'm afraid.
All I can say for certain is that it's either Asus's or AMD's fault, and probably related to voltage issues from the mobo to the CPU. If Asus at least provided unlocked BIOS and AMD provided unlocked CPU it would make our job of diagnosing the issue easier.
But corporations being corporations - my next laptop will be a FrameWork (https://frame.work) one.
Since my last post in this thread, I experience the pGSoD (p = pseudo) twice a day on average. I just deal with it at this point, and will continue to do so until I replace this laptop when personal finances permit.