Try some these.
Flash BIOS F1 reboot to BIOS and set Optimised Defaults and boot to Windows.
(I just do this to make sure the corruption will be wiped by the downgrade)
Flash you intended BIOS (F3 or whatever) TWICE. Just for kicks.
Optimised Defaults again and boot to Windows.
Reboot to BIOS and set CPU Speed + Voltages. Leave RAM untouched for now. Boot to Windows and run some bench.
Reboot back to Windows and Set XMP leaving the Timings to Auto for now. Adjust RAM Voltage to 1.45V, VSOC to 1.1V, and give VDDP some boost like 0.100 and try to reboot.
If you fail, try to Disable XMP and adjust the Timings.
This what is meant by tweaking one at a time.
Ryzen hates combined tweaks in one instance.