7950x3d and rtx4090 - not getting expected performance

If I were in your shoes, I would, quite franky, but you have to be comfortable with navigating the BIOS options if you decide to do so.
The reason I would:
There is an eco mode on these boards that limits the power draw. It is turned off in your settings, as shown in a previous screenshot. But the bios on these is known to behave strangely sometimes…

Clearing CMOS won’t harm your system, it would just clear your bios to factory defaults.
Among other things it resets any advanced, non-standard power management entries.

Only you can make that decision, though.

Edit:
Here is a screenshot from the motherboard official manual that shows how to perform a clear CMOS, should you chose to do so:

Clearing CMOS will do a memory retraining, so the first time you boot may take up to several minutes before the BIOS show up. Just let it do its thing until the monitor turns on again.