I am getting so frustrated at the total lack of progress in Oculus trying to find a solution as to WHY the link cable will not work. EVERY, and I mean EVERY possible effort has been done to find a solution. My new system is a Intel i9-11900K CPU and a ROG (Z590) Maximus XIII Hero motherboard. ALL drivers have been updated and re-loaded, as is the Nvidia drivers. The USB Hub, Host, and Root Hub controllers have ALL been re-installed. The USB settings in the Bios have been checked. ALL the Oculus software removed and re-installed, et, et. The USB-C ports are working OK, as I have plugged in a Portable HD to the ports and work fine, and the link cable DOES charge the Quest 2. I have also tried ALL the USB-A 3.0, 3.2 and 2,0 ports with an adaptor cable. No matter what huge efforts I take, the same old problem, 'PC not connected' and a Win10 box 'Device not recognised'? It JUST GOES ON AND ON! My previous system, the Quest 2 did work on the PC link, but the Intel i7-6700K and the GTX980Ti did struggle, BUT it worked and quite well! I used the PC link almost 80% of the time, so it is important. It HAS to be a Oculus software problem that is NOT compatible with the new Z590 motherboards. As far as I am concerned this Quest 2 and genuine Oculus link cable is NOT fit for purpose! I want a RETURN for a FULL REFUND
Sorry to hear about your troubles. Maybe does not help but my asus maximus hero xi Z390 works best with Link connected to it's usb3.1 gen2 type-c port. Usb Link speed test = 2.5Gbps. See my signature for my other PC specs. What gpu and psu are you using? I'm sure you have done this, but make sure you disable all your USB power savings. Also, if you have a good router/wifi setup you may want to try wireless with Air Link.
I doubt you'll get a refund if you are outside the usual 30 day return window but I guess you could always ask Oculus Support anyways. I have heard of a few compatibility problems with some z590 mother boards so you may want to contact Asus support and ask for some help.