UPDATE: I did a test on another board and ran into the same issue with not being able to boot into Windows on default settings, on a newly flashed BIOS that I had not used before.

As with my original board I got blue screens with thread exceptions and the like happening.

After making the changes I outlined in the original post is when I could boot to desktop and everything was working, just at high voltage and consequently high temps.

I’m talking to Intel support now as I guess as some comments have pointed out, the CPU is very likely defective 😞

MCE is enabled, I even tried it off and this morning I actually did a CMOS clear again after the replies here just to be sure it’s not a bug in software.

With MCE on and MCE off with everything at auto I can’t get into Windows. The BIOS voltage readout was at around 1.42.
Which from the comments yesterday is about normal and what’s expected.

I then made the changes back to what I had as stable (1.5+) and I can boot into Windows at least.

It’s really weird and I also feel like for my setup I shouldn’t get a ton of throttling, but on heavy workloads it will frequently go down to 5GHz or 4.9GHz and stay there.