Snag, this video is a pretty good starting place:
PimaxVR over Steam for sure. I've had good success setting the Pimax Play refresh rate to 120hz but then in the Pimax Play Games tab restricting the frames to 1/2 framerate. That give you 60hz in game which is plenty and seems to cut down on the stutter a lot.
If you were using OpenXr tools, you can't use that now since it's already incorporated into Pimax Play.
Also, definitely enable quadview, good framerate boost. I use the quality setting. The Pimax centering and eye tracking in-game is not for the Crystal Lite so leave those off. Note you have to set the quadview tickbox to on in-game in the VR settings tab.
I leave Pimax Play rendering quality at 1.0 and in-game rendering to 1.0 but depending on your settings in game you can try and bump these up or down a little to get the framerates and quality you like.
I like using DLSS and DLAA in game, helps with framerates a lot. But, you need to get the new DLSS 4 runtime and set the preset setting to "F", "J" or "K" depending on your preference, especially if you have an Nvidia 400 series card or above. Otherwise DLSS and DLAA are too blurry and there is ghosting. "J" and "K" have a performance hit, so I use "F". Search for "DLSS 4" in the DCS forum and it will tell you how to do this. It's not too complicated.
Next time we're on we can walk through settings.