Yes, you can connect the Galaxy Tab S8 Ultra via USB-C to a USB-C screen. DEX will then run on the 2nd screen and on the

The connection from screen to screen normally goes via WLAN (with Smart screen I can mirror the mobile phone on the monitor of the Tab S ULTRA, and operate it on both devices. But when I connect TAB S10 and TAB S8 Ultra via USB cable, the TAB S8 ULTRA offers me the applications Gallery, Photos, MTP Host Downloads and Smartswitch. Via cable I can probably only move data back and forth, but not control the screen remotely, for that I need DEX or Smart View Second Screen, but they work via WLAN. I only tested it briefly, but I'm sure you can get more information from Samsung or Digitec.