I have a laptop connected to a thunderbolt hub and from there a usb-c cable goes into a usb-c kvm switch

The other connection is from a GPU with a DP to usb-c cable. The gpu is used in a VM if that matters.

The kvm switch is then connected via DP to my monitor.

However the monitor is not recognized in my vm (runs windows) with that cable.

Connecting HDMI from the gpu to the monitor works.

Using the DP to usb-c cable from my laptop direct to the monitor also works.

What could cause the issue? Is there some tool I could use to see if the machine recognises the cable and maybe reports an error or so?