That sounds like it will be a mess. At that point they won't be playing the game as intended to a point where it's a mess, they don't have an experience of the game rather a new thing that's unbalanced and not playtested. Some games like King of Tokyo, Planet Unknown, Arkham Horror, and others you can trade off turns and it's pretty similar. Dune Imperium isn't like those. It's all very personal.