This is very similar to this topic discussion:
I’ve having a very similar experience, but my fps is locked at around 18 fps. Doesn’t matter if I’ve got the settings at Ultra or Low. Only thing changing is the quality of the display. I’m using the developer mode FPS counter.
My system is an AMD Ryzen 3700X w/ 32GB, Motherboard is a GIGABYTE B550I AORUS PRO AX, GPU is a NVidia 1080 with current drivers, and my VR Headset is a WMR Lenovo Explorer.