Jedec was standard for SPD before intel created xmp.
The board is posting cas 15 with the memory that has jedec #6 as cl-22.
Which tells me the bios is no good with the memory or the memory is garbage with cas 22 which is what I suspect is the issue.
Even my corsair Hynix (which You hate) does better than this with my 2700x.
Just sayin.
Xmp is just a tested OC profile generally for Intel because Intel IMC has always been better than AMD imc.
Even AMD ddr3 ram didnt improve FX imc and was pretty much a wash.
Amd boards just change the naming xmp to docp but should still act the same unless the AMD imc is weak or weaker than Intel which is till the case even today.
Theres nobody running 4300mhz memory frequency on AMD with cas 16 and if so, either rare lucky or extremely cooled.