I do have that issue with lagged bios. It happens when you turn off CSM. A workaround is to press Ctrl + Alt + F6, this will lower the resolution and make it faster.
It is weird that you are getting such crappy results. I used to have a MSI X570 Gaming Plus, and that board was not able to properly run my 5950X and my 4x8GB RAM (I had it stuck at 3400Mh CL, wouldn't post beyond that),,
any change on PBO resulted in huge losses in performance in some multicore apps like cinebench, getting all core clocks of 546Mhz. That's why I switched to the X570 Aorus Master and my ram is running at 3800Mhz CL16.
I tried the F32a bios, it made my master able to boot beyond 1900 FCLK but with whea errors, also voltages were increased to cpu compared to F31.
You should share screenshot of your bios settings, also run PBO like this 210 / 140 / 145, scalar auto, curve -5, max boost override 0, platform thermal limit 90. Use cpu voltage in auto and cpu llc in auto.
Also it might be your windows settings, disable fast startup in power and sleep settings, and if you use gigabyte fast boot disable that.