Yes, although the UltraStudio Monitor 3G uses a USB type C connector, it is a Thunderbolt 3 device which means that you need to use a Thunderbolt 3 (or Thunderbolt 4) cable and you need to connect it to a Thunderbolt port on your computer (a regular USB-C port won't work).
Note that on the 24-inch M1 iMac with 4 Type C ports, 2 of the ports are USB only and the other 2 are Thunderbolt ports (the Thunderbolt ports are marked with a lightning bolt symbol above them). On earlier Intel-based iMacs from 2017 onward, I believe all of the Type C ports should be Thunderbolt 3 compatible. And then even older iMacs had Thunderbolt 2 ports (which use a different connector also used for Mini DisplayPort):
https://support.apple.com/en-us/HT201736Apple sells a Thunderbolt 3 cable here:
https://www.apple.com/shop/product/MQ4H ... cable-08-mBut cables from other manufacturers that support Thunderbolt 3 data transfer (40 Gbps) should work as well.
If you are using an M1 based Mac, also make sure you have installed the latest version of the Desktop Video drivers, as there were various updates to add compatibility with the M1 processors as well as recent versions of Mac OS.