kimura9988 something like that. But like I said for video you will notice it only on the best 8k scenes. Not the blurry ones. VR Bangers latest vids for example. So the percentage of perceived difference can be 0% a lot the time (apart from the colors). Let me explain:
I mentioned gaming mostly because it becomes very apparent that the screens are just better when there is enough resolution, bitrate and sharpness being fed to the device. Also, 8k video is generally not enough to max out the quest 3 or the 8kx if it's not perfectly in focus and the pixels aren't utilized to get the upmost of the resolution (very few 8k scenes manage that).
One way to see this in action is by zooming a video out as far as it goes. If the quality increases it's a video limitation if it doesn't than it's a headset limitation.