Hello. Thanks for coming back to me. So when the Hub4 is set in router mode, the wifi is switched off, and one computer is connected via a Cat6a cable, I get 900-1000Mbps to the hub (left side of Samknows Realspeed) and 600Mbps to the computer (right side of Samknows Realspeed).
The computer has a 10 gigabit card, and the cable is Cat6a, and I have tested that exact physical connection at 10Gb by transferring a file from my NAS which also has a 10 gigabit interface, so the actual physical cable and interface can definitely support multigig speeds (happy to share screenshots if useful). Something is going wrong at the Hub end, and I can't work out what.
Thanks again for your help.