The GPU is not going 100% for 4K video.
I just beefed up my WiFi with an Intel AX210 WiFi 6e card. I tried using AirLink - no apparent difference than using the cable.
I turned on Media Streaming in Windows 10 (DLNA) and added my video folders to the library. Streams 5K and 8K videos are streaming smoothly with higher frame rates then either AirLink or Link when using DLNA in Deo VR.
Same with other VR video players that support DLNA. The App Labs one just added SMB support as well.
I'd say the bottle-neck culprit is the Oculus Link software at this point.
Maybe I'll play around with Plex. Or see how SMB works with the Apps Lab viewer and hope the others will add SMB support.