Sadly it has done it on both, W11 and Endeavor. I was hoping that moving to Linux would resolve it, but it persisted and I decided to go back to Windows. The one thing I have noticed is that right before rebooting, there's about 1-2 seconds of extreme latency, even impacting the mouse pointer tracking. As far as I remember, the hardware pointer is handled by the GPU, making me strongly believe it is at fault.

I do have some hope though, it seems to have become less frequent with a GPU driver update that happened at some point within the last year (I have Windows updates blocked and manually update infrequently because of all the MS shenanigans).

When I first built the computer, the reboots would happen twice a week, but at this point I have only encountered it once or twice a month.

Here's hoping AMD's driver team has been working on it, that it's not just luck, and truly not hardware issues - I wish I had the skills to actually diagnose what is going wrong.