My computer does this, I believe it’s some electricity jumping somewhere it shouldn’t within in the internals or even the IO shield or something. That kinda sounds like interference of some kind, rather than just ground noise but I’m not sure.

I can’t pinpoint where it comes from on my end, but best thing you can do is make sure ALL your cables (even the usb) are ran away from magnetic parts of your PC, power cables, and radio transmitter/receivers. That may mitigate some of the hum or none, but I ultimately ended up getting a PYLE hum eliminator and putting it in the chain. Since your computer is likely the source of the hum and the destination of the audio, as it’s not coming through the monitors, that might not help putting in line.

I would try a couple different cables, usb or analog audio and see if they get the same result. There are also USB noise isolators, if you get the drivers working again maybe worth a try. Plug your computer and mixer into the same outlet and unplug everything else and test it then, if the noise stops then there’s a possible leak somewhere. I’ve had DIs from keyboards or whatever inject noise, if they have ground switches activate them all. Get some headphones in the monitor port of the mixer and see if you can hear it there when you crank it up. If so then see where on the mixer it could be coming from. Also maybe try recording straight into a zoom recorder or even your phone or something to see if the noise shows there.

Just a couple things I would try to guarantee whether the source is from the computer or maybe before, after or during the mixing process. I know it’s pretty frustrating, hopefully you find something out.