The docking station is meant to be plugged directly into a device (laptop, tablet, etc.), it does not work via the screen.
As for resolution, USB-C has no video output, only HDMI supports up to 4K 60Hz.
I have been working with the port for 2 months. I stream film data from ext. HDs to DaVinciResolve and do colour corrections in real time. I haven't noticed any drop in performance so far. I am very satisfied.