Windows 11 should not have anything to do with the performance of your cable. I've been on Windows 11 since the early beta with no issues. It's barely more than a UI update with a couple of improvements to the actual OS. While it is absolutely possible that a driver or system file got corrupted during the update, it is unlikely. It is best to treat this like any other hardware error.
What I would recommend first is uninstall the device. Bring up your device manager (windows key + X, select Device Manager), and find the entry for the cable. It will either be under "Sound, video and game controllers" listed as the Rocksmith ESB Guitar Adapter, or possibly under System devices or Universal Serial Bus controllers as the "Unknown USB Device". Either way, right click on the listing for the cable or unknown device and select "Uninstall Device". You'll get a message asking if you are sure you want to uninstall it, say yes. Once it is gone, reboot the computer. Once it reboots it should find the device and install the proper drivers.
If that does not work, and you still get the Unknown USB Device error, unplug the cable and inspect it thoroughly. Check the plug first, look for anything that might be inside the plug or for any damage. Check along the length of the cable, especially at the breakaway section. Make sure it is all plugged in properly and there are no debris inside the port, and no damage. Check the component hosing (the wider section a little further along the cable that has Ubisoft embossed on it). Look for any signs that it has been bent or damaged (my dog chewed on my cable at one point and broke that section, which ruins the cable). Chances are if it is still giving an error it is likely there will be physical damage somewhere to the cable, and it will need to be replaced.
Also, maybe try plugging it into another USB port on your computer, in the off chance that there is either a driver or physical issue with that port.
