I also have a 5800x3D paired with a 3090 and an HP Reverb G2. I was also experiencing subpar performance in VR. Two settings changes made the most difference. I observed 10-20 fps improvements. I am not something you would see the same.
I disabled both virtualization(SVM) and multithreading (SMT) in my bios. Disabling virtualization led to the biggest performance gain.
Good luck.