No changes to VR settings but now frame rate dropped?

VR Quest 2, i9-11900K, RTX 3090, 32GB Ram, 2TB Gen4 SSD and fast BB. Very latest Nvidia driver (today) ver. 527.37. After setting up the VR with Meta App, Nvidia settings, Oculus Tray Tool and Open XR Toolkit. Last night flying in VR over London I was excited that I was getting 35-40 FPS, smooth, no shimmering, and sharp graphics. I thought to myself, I have cracked it! Flying this morning after the Nvidia update, and not happy. Same aircraft over London, BUT the FPS has dropped right down to 20 to 25 FPS, with shimmering. I have re-checked ALL the settings, nothing has changed since last night. Has the Nvidia 527.37 update caused this? I have also checked the Nvidia graphics settings and have not changed with the update. What’s happened please?

The obvious thing to try is to roll back to the previous Nvidia driver. If that fixes it you will have confirmed where the problem lies.

Shimmering depends hugely on lighting conditions, maybe they were different?

I had the opposite with the 527.37 driver update…very smooth performance, great FPS and no shimmering or wobblies for a change in MR using the Toolkit and DLSS Quality (5800x3D, RTX 4090, G2 headset).
Then again, this sim is never the same twice, especially in VR. It could have been either a hardware specific issue with your rig and the new driver, or maybe just server issues.

So you think 527.37 is the best of the 4090 drivers so far?

Well 527.37 seems to work OK for me and I’ve gone back to using DX12 too.

Update. I have re-checked ALL the settings, Oculus Tray and OpenXR Toolkit, Meta and Nvidia settings, FS on TAA and Medium settings. Exactly the same on my i9-11900K/ RTX3090 PC. I rolled back the Nvidia driver, no change, re-installed latest driver. The settings showed from ‘VR Flight Sim Guy’ on You Tube with a RTX3070i/Quest2 system and he was getting 40 FPS! Very very smooth! My VR still looks terrible, struggles at 19 - 24 FPS, loads of shimmering in all lighting condition, juddering and the graphics look washed out. Totally NOT enjoyable, and I regard it as unplayable! So I will forget FSVR, pity. On the plus side FS Monitor mode is a joy, crystal clear in 4K and all at Ultra settings, very smooth, stick with this only. As a comparison to FSVR, IPACS AeroFly in VR is a joy! Flying around the Swiss Alps (scenery update) in VR is fantastic, crisp, clear and very high FPS. If IPACS can do good VR, why not MSFS VR? I will play MSFS in monitor mode and AeroFly in VR.