When CK3 was announced for consoles, players were skeptical as to how successfully the game would port, especially with USI in mid. Paradox have taken care of that problem superbly.
As you would expect, user interface and controls were core components of the adaptation from PC to console. One of the main aims was to create a UI that was easily accessible and facilitated fluid gameplay. There is no set standard for UI and controls for Grand Strategy Games on console, with most approaches being subjective and Paradox have taken an approach that suited the unique Crusader Kings Gameplay.
The main features of the console User Interface in the Crusader Kings 3 console edition are not keeping the PC UI and using the controller thumbstick as a virtual mouse, and instead introducing the D-Pad for in-game navigation.
Furthermore, with so much information available in the game, it's important that players can flick between the various tabs and pop-ups easily. To that end, Paradox have adjusted every ta and pop up as to not be in the full-screen.
Additionally, moving between the various maps, and other such core mechanics of the game, will be done via the Radial Map Wheel. This way, players will be able to exhibit prompt reaction time to in-game events and act accordingly, the same way PC players can.
All in all, the way the User Interface looks now, it seems like the port will be a successful one, and Paradox must be commended for their out-of-the-box thinking when designing the console edition of the game.