Heyo,
I came across an issue with Unity games and VR on pimax and some WMR devices. Got reports of this for the game I'm working on as well. The workaround is putting the tracked pose driver of the head on Head instead of HMD Center Eye, but this isn't a proper fix of course.
Here is the post I found:
https://www.reddit.com/r/Pimax/comments/qhkrfp/pimax_unity_xr_plugin_issue/?utm_...
If you want to help getting this fixed, could you make a bug report to unity and mention case 1377372 so they can link them.
My case was closed because I was unable to submit my project.
If you don't want to do this, at least it's a good thing to look at (: