Poor performance in SteamVR (not stuttering related)

Update: This is fixed.

I recently reinstalled Windows 10 and have encountered some very poor performance in SteamVR that was not present before. I am using a Quest (original, not 2) and it occurs both over Oculus Link and Virtual Desktop. I've tried everything I can think of, so I am hoping someone can help me with something I have not thought of.

Specs:
CPU: Ryzen 3700X
GPU: GTX 1080
Memory: 16GB, 3200 MHz
Windows 10 Home

Example of the performance: https://i.imgur.com/oqlCqI2.png

I shouldn't be seeing these poor FPS in the void, with no GPU load. This is an issue even before a game is loaded up. Steam Home is disabled.

I have also verified this issue is not present while using Link and VD outside of SteamVR. Beat Saber via the PC Oculus store, for example, easily runs at full speed at high settings. Via SteamVR it's 30-50 FPS on lower settings.

Other things I've checked, but have not made any improvement:

• Turned everything off and on again
• Downgraded Nvidia drivers to 446.14 with clean install using DDU (though now I'm back on the most recent 465.89)
• Turned down all settings and supersampling - in SteamVR settings, and per game settings, and in-game settings
• Forced SteamVR motion smoothing off in per-game settings
• Opted into the SteamVR beta branch
• Verified other games (non-VR) run as expected
• Verified CPU, GPU, and memory are running at expected clocks
• Completely closed programs like iCue, Afterburner, RTSS, Malwarebytes, Geforce Experience
• Checked there's no unusual settings in the Nvidia Control Panel (vr pre-rendered frames is set to 1, but changing it has no effect)

What else could possibly be causing this?

EDIT: Well, I resolved it. I uninstalled SteamVR, removed all the files (including those in Documents folder), and reinstalled it. Works fine now.

I guess this is a lesson. Even if it's a fresh install, you should always try an even fresher install.