4000mhz is actually impossible for a i3 10th gen on this budget board. I tried 4133mhz but it was unstable. Dunno if my voltage is too high.
Specs:
CPU: i3 10100f
RAM: DDR4 2x16gb Kingston Beast fury (XMP is 3600mhz cl 18, but I manually overclocked to cl 18 4000mhz)
Motherboard: Asrock B560M HDV