i have an i7700k at 5ghz and a RTX2080 not overclocked, it runs a Valve Index at 80fps mostly but often dips lower, FPS VR tells me that my GPU is at 65% and CPU up to 40%, which is being bottled necked the CPU or GPU? I also run crewchief, Simvibe and FPS Vr, Iam not sure if FPS Vr is showing overall CPU or a single thread.
Your CPU is bottlenecked. You can't see the true impact on the CPU with FpsVR. Be shure to set shadows and car reflexion to lowest, then you should easily reach 80 FPS. For more information look at the settings posted in VR tweaks thread here.