Macbook Pro 16" USB-C to DisplayPort not working
You just need a simple Type C DisplayPort cable.
The confusion comes from how “USB-C” was implemented.  USB-C is just the physical port type.  The ports on your MacBook Pro are actually Thunderbolt 3 ports and they use a Type C connector.  Thunderbolt has several signals:  PCIe, USB 3.x, DisplayPort and Power.
So, that port is natively outputting DisplayPort and the adapter you purchased is an actual video adapter that connects to USB and outputs DisplayPort.  It’s not working because your Mac doesn’t have the drivers for that particular adapter.