Yes, I think most of the changes would be the dialogue in those scenes. At the very least the final half of the hangar scene, when he asks her to join her. It isn’t to join him and rule the galaxy, but to come with him and run away. And if you listen to his dialogue on the Death Star in kind of flows into that idea. He wants to run away because he thinks he’s too far gone, and he’s trying to convince Rey is too.
And I think their Death Star duel would be more motivated by Rey wanting to fight Kylo rather than Kylo wanting to fight her. I kind of imagine a version of the story that leans more into Rey slowly being corrupted by the dark side (through the visions, the dagger, etc.) over the course of the movie.
Kylo’s motivations could be like this:
Plan A - get Rey to run away with him
Plan B - if Rey refuses, kill her so he can claim the Sith throne/fleet.
At this point he may be accepting his fate, but sees Rey as his only escape. And if you’re going with a Rey Nobody edit, perhaps this is because he sees that Rey was never part of Palpatine’s plan. A variable he didn’t account for, couldn’t see.
I also always liked the idea of cutting Kylo’s line, “The only way you’re getting to Exegol is with me”, and just have him destroy the Wayfinder because it makes you wonder why he does it. To protect his new fleet or to maybe protect Rey?
And it could be interesting if, through the visions, Rey and Kylo were more directly pitted against each other. Like Kylo could tell Rey, “either you will take the throne or I will, but one of us will kill the other”. And Kylo is leaning into Rey inevitably giving into her darkness, into power, to get what she wants/save who she loves. It’s inevitable like Palpatine returning was inevitable. Power corrupts. Join the Sith and save your new family vs Be a Jedi and sacrifice your life or theirs.
Again, I think you could spin it several ways depending your version of Rey’s origin. If it was Rey Nobody, then Kylo would basically be like, “Palpatine is the conclusion of a plan a thousand years in the making. My family was a product of the Force itself and were still corrupted by him. You’re no one, how do you think you can resist him?” In my mind the dark side/Palpatine/the Throne is very much like a Sauron/the Ring situation. This powerful corrupting force. Like a black hole that drags down any good intentions. But it being representative of our negative qualities like greed and selfishness that we must always live with and struggle against. And Rey being representative of how anybody can be consumed by those things. None of us our immune.
(Speaking of black holes, I think it would be interesting to depict Exegol as a planet orbiting a black hole to make it more visually distinct and to add something to the idea of why Exegol is such a powerful nexus of the dark side.)
Ever since your idea about the Sith Throne, I like the idea of a big theme to carry through this movie is Selflessness vs Selfishness, and I think this would play into that well. Kylo wanting to just get away from it all also kind of makes me think of how Han is in ANH, only to show up and save the day in the end.
Also, sort of unrelated, but if you didn’t want to use the “dyad” term you could use a “vergence in the Force” as a more generic term for some special for thing. When Palpatine says “dyad” his mouth is out of Focus so it could be modified without it being super noticeable.