Testing 90 FPS mode using a Lenovo Explorer.
Results: It goes between 80-90 FPS and dipped to 60 at one point.
On this system I may change back to 60 FPS mode.

Specs:
i5-10600K @4.1 Ghz (Default)
RTX 2060 Super
64GB RAM
Game installed on a SATA SSD

I am using OpenXR Toolkit.
https://mbucchia.github.io/OpenXR-Too...

In game settings:
VR Low as a baseline
Anti Aliasing: SMAA
Super Sampling: Ultra Quality
Upscaling Quality: AMD FSR 1.0

Enable foveated rendering, wide, in OpenXR Toolkit.