Since you’re using a 3080 and you’re forced using a Nvidia driver with known bugs in VR, you’re stuck until Nvidia makes corrections. However you can already get better perf in disabling MSI Afterburner (and any other similar tools). In addition you might want trying out an older Nvidia driver
NB: the problem with VR perf is not just single core CPU maxed out, it also has to do with presenting 2x views to the headset and this doesn’t linearly scale by the resolution. In effect, the GPU has to draw the same scene twice from a different angle. This means any cache optimization for the first view don’t translate to the 2nd one for example. On top of this there are synchronization limits to waiting before being able to ending 2 views at once. A low CPU and GPU use in VR is not because of bad optimizations, not always, it is most often because one is waiting for the other.