A couple notes.
 
You have CPU Multiplier Control set on "PerCore", which tries to set fixed speeds on specific cores. I believe it tries to figure out what your "best" cores are and put the highest multiplier on those. In your case, I'd be surprised if any of your cores can't do 6GHz, so I'd opt for the "RatioLimit" option and then just set 60 on the first two and 57 on the rest. This will set it to do any cores up to 6GHz as long as the work-load is on 2 cores or less.
 
13900k, but you get the idea:

 
As for your temperatures, what load were you running during your HWiNFO screenshot? The variance in temperature core-to-core is very high. I don't even see that if I'm running Cinebench single core tests. This is usually indicative of a bad mount (bad thermal paste coverage, uneven pressure of your block, or sometimes really bad IHS solder inside the CPU. The only other thing I can think of that may cause this sort of thing is if the voltages are just completely out of whack. What voltage settings do you have right now? What settings did you try to lower Vcore? Did you set an override and see if a fixed voltage would work? You should see measurable differences on VIDs and package power by doing that. Of course going too low will lead to instability, but I've tried the global adaptive offsets and didn't see any change at all even on 13900k (which is supposed to work in this BIOS lol), so I don't think that'll work for you.
 
Also, as a good thing to try, I agree with Talon on the power limit setting.

1.41 seems too high to me. I would think you could override down in the 1.3-1.35 region, some people are running even lower, but they have the proper microcode and stuff. The other option is to try and set voltage on auto and mess with the v/F points, but if you go too low (which is a mystery number because evga doesn't expose actual voltages), I think it ignores it and just runs auto, which is too high. I can generally set and test mine down to the point of instability though, but it seems very coarse in the adjustment for me, plus it seems like it's still doing a global offset the way I have it set up, even though it's not supposed to... Which is the part of this bios I think is still broken even for 13900k.

Anyway, if you can get it to drop the voltages a bit, it'd be interesting to see if it still hits crazy Temps on a couple cores (especially if it's the same cores every time) because that may confirm it's the solder TIM in the IHS. If you take the block off again, take a picture so we can see how the paste looks

I have adaptive boost and TVB disabled (I left TVB voltage optimizations on auto). I think you'll need more than 251W to get to full speed. You got it to stop thermal throttling because it's power throttling with the limit you set. You may want to try 280W, and then keep dialing the override down if it's stable. Just be careful, as it will stop being stable during 6GHz boosts before it stops being stable at all core loads when using override, especially if it's throttling and dropping clock speeds you will have issues opening a web browser or running single core bench but all core will be stable lol

Well, the most likely culprit is that the board isn't reading or setting V/F levels correctly due to the wrong microcode (no BIOS support from EVGA). I don't have time today, but maybe someone can run their 13900k and see if they see the same flags thrown in hwinfo. Also, it's possible that there are fast pulses that hit the power or thermal limit that just aren't being caught. You can try to increase the monitor speed, but it only goes so fast. That said, I'd be curious what your other 14900k does.

Anyway, if your Temps are under control with a lower override set, I'd start ramping up the power and see if you can get to a point where you're not dropping clocks and the temperatures are still bearable.

If the voltage is on auto and you run flat out no power limits, I'm betting it'll try and pull at least 390W, maybe more if not thermal throttling first. That said, the whole point of 14900k was that it's binned to not need that much. So most people I've seen running override voltages are much lower. I would expect it to thermal throttle if it's trying to pull over 325W on your setup. So if you get the voltages low enough and are still stable, you shouldn't have to even set a power limit. I'd keep trying, but you may just find a performance limit for your board until a BIOS update with a new microcode comes out (if it does) and it may be worth it to try and sell this one to get one that supports your CPU.

14th gen is not supported by EVGA on Z690. 

ilukeberry
14th gen is not supported by EVGA on Z690. 

I ran 14900KF on my Z690 Dark but needed modified bios which someone made for the Z690 Dark Motherboard. It ran ok but you couldn't overclock it at all. I still have it so I could run it in my Z690 Dark and it would run just fine. But now I am running 13900KS. I didn't have any stabilty issues with it in my Z690 Dark Motherboard BObaganoosh.
http://www.3dmark.com/spy/43403261
http://www.3dmark.com/spy/40803266