The problem lies with USB-C supporting so many different video output standards, and different laptop makers choosing which one they support, and if they support one at all.
Take a look at the list of USB-C supported alternate modes:
In that list you will find three video modes, DP, ...
Go back from number encoding of the device tree. For example, my webcam is at /sys/bus/usb/devices/3-1.1.2, which means it sits on bus 3, port 1 of the root hub of thus bus, port 1 of a hub below the root hub, and port of another hub of the last one.
Or with lsusb -t:
$ lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M
/: Bus 03....