I have a Pimax4k as well. No, HMDs can’t match monitor resolution just yet, but the Pimax has come the closest.
I actually use 3000×3000 for GRW, but this means I’m averaging only 28 fps on gtx1080. I’ve come to tolerate 30 fps for third person games, but want at least 45 for first person.
I’m still running the old 1.1.92 piplay with default 1440p res in steam (no supersampling). This is performance efficient, and is feeding the correct 1440 signal the upscaler chip converts to 4k. Instead I render the games at high resolutions, and find subtle improvement the higher I go.
To maximize clarity in vorpX for the Pimax, become familiar with the Image Settings page of the Delete Key menu. I usually crank the Sharpening slider all the way to 2.00 for good results. Try the Crystal image settings. Normal is often best, but in a few games Advanced can look better. And use the Brightness/Saturation sliders to improve vivid color.
Also note that GRW has it’s own Sharpening slider in settings, though for me setting beyond 35% was even too much.
Anyway, glad you got it working. If you have further questions or trouble with the 3D let me know.