type c for using hub

Hi-in order to help you better, could you tell us what model/year of Mac Pro you have, which is found under "About this Mac" under the large Apple icon at the top left of your screen ?? -- and is it portable with a built in screen, or not ?? I'm guessing it's a pretty recent model of Mac Pro. Dumb and basic questions, I know, but you have to start somewhere. I don't think that dongle exists, as far as I know. Usually you'd get either a USB-C hub/dock, or Thunderbolt 3 hub/dock, with various connectors on it, usb 2.0, DisplayPort, miniDisplayPort, Ethernet, hdmi, etc. I've also never heard of a USB-C input either. Although Thunderbolt 3 does support USB-C and MiniDisplayPort via the appropriate cable, which would be USB-C male to miniDisplayPort, you'd have to check your Mac Pro's specs to see if does in fact have a Thunderbolt 3 socket on it. Again, I don't know what kind of Mac Pro you have. I know you can get a USB 2.0 type A to USB-C female adapter, but that's it.

john b

Use extreme skepticism when connecting displays (that you would like to use for High-Performance graphics) to an external Dock.

Many of these devices bypass the accelerated display Hardware entirely and instead create a simulated display in RAM, and use DisplayLink software to send the display updates to a DisplayLink chip in the Dock, where it is turned beck into a "Legacy" interface and sent to the display.

Best graphics perforce is obtained using DisplayPort family or Thunderbolt interfaces, but converting displays from one version of ThunderBolt to another is a guaranteed losing proposition.

If all you want is big spreadsheets, this may not be much of an issue.