I was able to get it to work in VR by installing Reshade with OpenXR checked, then copied C:\ProgramData\ReShade\ReShade64.dll to the VAM.exe location and renamed it dxgi.dll.
Also updated ReShade64_XR.json to reflect the path to VAM
C:\ProgramData\ReShade\ReShade64_XR.json:
{...