Alrighty, have some interesting updates on this, unfortunately none of them are good.
What first is odd is that Cores 5 and 6 are defaulting to 60 multiplier instead of Cores 1 and 2. See screenshot below.
Also, Cores 4, 6, and 8 are thermal throttling pretty badly. I've tried lowering clocks and vcore, but they just keep on thermal throttling. At the same time, I'm getting a Power Limit Exceeded on all of the cores. So I'm getting both Package/Ring Thermal Throttling and Package/Ring Power Limit Exceeded. Screenshot below...
I'm using a Thermalright Contact Frame, and I've tried reseating the CPU in the socket as well as the new 420mm AIO. Temps don't change. Can't even get through a single Cinebench R23 run without it throttling pretty badly.
I'm not sure if this is due to bios wonkiness, but I haven't seen anyone else, who's testing out the 14900k on either the EVGA Z690 or Z790, getting the same results. I've ordered a new 14900k, it's possible I got a bad chip, so at least I'll be able to run out whether my current is just a bad cpu.