Yeah I tried increasing voltage, decreasing voltage, resetting BIOS to default settings, etc. I tried everything you could think of but nothing helped.
I did see a post on reddit from someone else with the same MCE hardware errors in Linux that I was getting, with the same random rebooting, and their 5900X ended up dying too.
In a sane country, a terms of service doesn't waive your rights to your legal minimum protections including privacy rights. In USA, I'm not so sure.