Let me be more specific; the part of the graphics card in your pc that is responsible for decoding the 8k h265 video stream into a working image, is also simultaneously used by virtual desktop for encoding another H265 stream which is to be displayed on your quest.
Virtual desktop us mostly used for gaming I reckon where other parts of the GPU are used, and the media component only has to encode the rendered frames to a video stream in which case there is no bottleneck.
P.S. Wireless = best indeed. I posted my config here. https://discuss.eroscripts.com/t/how-do-i-connect-my-osr2-to-my-quest-2/73369/6