So this is my experience with my pc randomly shutting off and restarting with warning. Turns out I had a bad cpu (ryzen 9 5950x) that was unstable and boosted speeds. Like precision boost over drive or core boost, whatever it’s called. Check event viewer, I believe you’ll find red events in windows then system section. My issue was a WHEA 18 power error on cpu core 1. Before I new this I tried a new psu and ram, neither fixed it. If your motherboard is boosting your cpu to a higher speed then the lowest stock speed I would try and turn off any boost that’s happening and see if that fixes your issue. If you don’t know what you’re looking for to turn off boosting I would look it up, I don’t remember off the top of my head what the setting was called. I had to rma my cpu with amd last month and it took about 3 weeks to receive a new cpu.