Fortunately this Pimax 8kX can be set to 60Hz, Smart Smoothing off. Toggling the async render on/off usually gets the underlying application to render at a full 60Hz as well. Enabling VSync on the underlying application seems to reduce jitter even further. Everything syncs up super smooth and efficient.
Subjectively, I think this is way better than 64Hz, 72Hz, etc. With everything, even physical monitors at 60Hz, there should be little to no frame skipping.