If this were me…
I’d do a complete re-install - delete the partition and let Windows create the new one.
Then, before installing anything else…
Test the system with the tools mentioned.
Then install drivers (Nvidia studio, without the bloat), and then test again.
Then install Cubase, and then test again.
Somewhere along the line the issues will rear their ugly heads. Or maybe not.
Keep the system as lean as possible. Asus software is more concerned about the motherboard, the rest of the system has to look out for itself.
just to say I’ve got an ASUS X670 MOBO that’s running a 9950x previously 7950x -64GB DDR5 and it’s rock solid.
I agree with @Googly_Smythe . You should start from scratch again as in the end it will save you more time.
One thing you could do however before you do that is to go into your BIOS and set it at the Default settings, i think it’s F5 and then see how things run. AMD can be picky with RAM timings so just set everything to default and give it a go.
You can always reinstall windows as well but keep your programs and settings which wont take long either so maybe worth a shot before the full format/install.