A developer has managed to get PlayStation VR2's eye tracking working on PC and now has HDR partially working too.
The developer plans to release the eye tracking solution as a free and open source mod of Sony's official PS VR2 SteamVR driver called DriverEx.
However, HDR support on PC is currently limited as SteamVR supports 10-bit color depth but does not support PQ (perceptual quantizer) needed for a greater range of luminance.
Full HDR support for PlayStation VR2 on PC will require either Valve to add support for PQ in SteamVR or the development of a driver that connects to a different OpenXR runtime.