You don't actually have 6000MHz RAM. It's 6000MT/s(megatransfers/s)
DDR(double data rate) does two transfers per clock so 3000MHz gives you 6000MT/s.
You're running your ram at 3600MT/s so XMP is probably off. Turn XMP on and pray it's stable. Without XMP on your motherboard will follow Intel's guidelines. Intel only guarantees 4800MT/s with 2 DIMMS in motherboards with 2 slots, 4400MT/s with 2 DIMMs in 4 slot motherboards, 4000MT/s with 4 single rank DIMMs, and 3600MT/s with 4 dual rank DIMMs which is what you appear to have.
12700Ks have a slightly easier time with memory than 12900Ks due to the lower E core count but 4 sticks at 6000C36 is asking a lot of the memory controller so I wouldn't be surprised if it's totally unstable with XMP on. Just two of those gskill 6000C36 sticks is borderline too difficult for either of my 12900Ks to handle. The Samsung DDR5 chips used in those kits are pretty terrible.