Most portable devices of recent vintage (tablets/phones/notebooks) do support video over USB-C or Thunderbolt. Most desktops (including this one) do not -- the USB-C port is not video-enabled. You may be able to use a USB-C displaylink adapter (see below for example) but you can't natively send video output from the desktop system to a monitor over USB-C. You'll need something like you will find here: [URL]#:~:text=DisplayLink%20enabled%20products%20can%20be,the%20newer%20USB%2DC%20standard.  
Hi there, I just purchased a brand new Optiplex 5000 and decided to pair it with this beautiful 27 inches S2722DZ. I was hoping the two would work together via USBc but the monitor won't detect the OptiPlex. The screen works fine whilst using an HDMI or DisplayPort but the USB-C port is a bit awkward: it'll work with an iPad but not with an XPS, which I'm also using. Am I missing something? I updated everything and asked for support but I'd like to hear from you. Thanks, FB 
OptiPlex 5000