Z690 classified (evga)
i9 13900K (refference)
ram ddr5 128gb (Kingston, currently 32gb installed for test sake)
Bios version: 1E698208.bin
 
With i713700k it worked with dual 4090 and 128gb ram. this was on an older driver version 0.00 (provided to Steiger Dynamics).
 
with i9 it only works with 1x 4090 not with 2x 4090. the problem is the following:
it boots fine but starts flickering and boot looping after ~10 seconds every time. (on the old bios 0.00).
with the new bios, I can no longer access the bios and it gets stuck on error code 47 or 97 all the time when booting, or it randomly gets into the bios wich is hard to exit without seeing it. entering the bios with onboard graphics doesn't work. entering the bios with a 2070/vega64/970 doesn't work.

I am lost on what to try.