The latest version of PiTool (144 beta) which was supposed to fix compatibility issues with the Index controllers with Pimax headsets did not fix finger tracking or gesture toggle support in VRChat, and it seems like the default bindings for gesture toggle, turning and movement are not working according to the documented behavior.

Other applications which support finger tracking (e.g. SteamVR Home, Aperture Hand Labs, etc) are working correctly.