Turn off auto-pausing for minor events. If the game pauses every time someone gets a pop-up window, the session becomes unplayable for everyone else.
Crusader Kings 3 in a LAN setting is an unforgettable storytelling engine. The shared drama, the ability to coordinate schemes in real-time, and the joy of seeing your friend’s carefully laid plans go up in smoke are unmatched.
Consider setting Player Assassinations to "Difficult" or "Disabled" if you want to prevent immediate real-life arguments.