My 5900X caused my system to crash endlessly for 2 months, until I managed to fix the issue through sheer luck (it had to do with a very specific voltage settings in my Asrock B550 BIOS - could have been SOC voltage) and my system has been very stable for the last couple of months.
However, I clicked on the one-click overclock option in Ryzen Master yesterday which reset my BIOS. Having lost the setting(s) that kept my system stable, my 5900X is now back to the constant crashes I had to endure at the start. I've forgotten the specific changes I made to the BIOS that fixed the issue, because I was troubleshooting using trial and error and didn't log my changes.
I don't know what to do now. If anyone knows about the various voltage settings in Asrock's BIOS to fix 5900X stability, I'd be grateful.