Is there anyway I can profiling this game in VR mode? Very unstable FPS performance

My hardware
CPU:7950x
GPU:RTX4080S
RAM:64G DDR5
game on 1GB ssd
OS:Win10
VR using quest3 on quest metalink USB3.0 cable and airlink tested
Graphics: no anti alias, no haze/blur xxx, no grass, DX11 rendering
The performance is very unstable.

Sometimes I get a 170 fps on VR with zero frame drop, and sometimes I get 36 FPS on VR with very obvious stutter and a frame drop. It was so obvious that gun aiming air sim is impossible. And landing with 2nd gen fighters are very difficult.

It there any profiling tool to figure out where is the missing frames?