I think you would have to cut less than you think. If you never saw the movie before, you probably wouldn’t even notice the difference, pacing-wise. At the very least, you might want to insert dialogue here and there to replace some of the dialogue you remove.
I’ve thought about it, and you would have to cut a lot. Here’s everything you’d have to remove:
- The end of Palpatine’s conversation with Kylo (“She is not who you think she is”)
- Rey having flashes of her parents during the training scene
- Rey saying “I’ve seen that ship before”
- Rey hearing echoes of the TFA flashback when she touches Ochi’s knife
- Rey talking to Finn about her parents leaving on Ochi’s ship
- Almost all of the force bond lightsaber duel (it might have to be cut completely)
- Almost all of the hangar scene (might feel too abrupt without Kylo’s dialogue)
- Rey saying “He killed my mother, and my father”
- Finn telling Poe about Ochi killing Rey’s parents
- All lines where Luke directly addresses Rey’s heritage
- Most of Rey confronting Palpatine (he mentions their heritage a lot)
It’s a lot, and I’m worried it would make the film feel even more rushed than it already is. And like I said, Rey being worried about going evil is probably too generic of a conflict for the final movie of a saga.