„No headset found issue“ -> Select Beta mode for SteamVR, and validate the message from SteamVR asking to make it the default gateway for OpenXR that appears when you relaunch SteamVR. Next time you enable VR mode, your Pimax headset will be found.
Thanks to SweViver😉
Turn OFF: Windows „Game mode“ and „Hardware accelerated GPU scheduling“ and „G-Sync“. RESTART,RESTART,RESTART!
Use Pitool V1.0.2.087 and Pimax Experience 0.84
Make a new room setup in Pitool.
Turn HDR ingame OFF
Press Spacebar ingame to recenter the cockpit sight.
After all changes RESTART!
Otherwise you may find the answer you need here: