I posted some suggestions above, but to really find the issue you'll probably need to do some in-depth diagnostics. The usual fixes don't work, so I guess that's it for me. Good luck, I hope you'll find the root of the problem. Worst-case scenario, you can always strip the system for replacement parts - most of the peripherals should probably work fine.
like a 250 dollar kit back when DDR4 was Intel only
