I do like this idea and feel it’d have been much preferable to the theatrical, but I think to realistically get at it we’d have to essentially let the theatrical alone. In other words I don’t think it’d work to imply Kylo has mysterious orders from Palpatine.
If the key ingredient of the idea is Palpatine knowingly trying to drain the dyad, I don’t think the footage is there to establish what’s happening, as he holds his hands up in surprise to exposit what’s happening.
I think it would be fine to start the film with a mysterious “What is Palpatine planning?” (It’s the one mystery box that actually has something inside.) As I understand it, Palpatine has three different plans throughout the film, even though the film tries to play each off as if “This was my plan the whole time.” (Just like how J.J. treated Episode IX itself!) First - ignoring the stupid “I never wanted you dead” - he wants Kylo to kill Rey and then possess Kylo. Hence, “The Princess of Alderaan has disrupted my plans.” Later, he wants Rey to kill him and initiate a Spirit Transfer. Evil Plot #3 is sucking up the Dyad Juice and rejuvenating his body to look like his hot, young, clone “son” his old, withered, zombie face.
If we were to pick one, true “goal” for Palpatine to have - I agree with Hal that Palp’s surprise at the Dyad wouldn’t work if that was his plan all along. I still think that Neerb’s plotline from months ago makes a lot of sense. Palpy wanted to lure Rey to Exegol; everything about wanting to kill her is a lie created by Kylo. All it would take is removing, what? Two lines? “Kill the girl!!” And “Kill her!” during his phone call with Kylo. Given that Hal was shooting for a December release, it would be fairly easy to do.
Side note: Have we done anything to clarify why he can’t possess Kylo? It can’t be genetic, because he was controlling Snoke just fine. If it’s because Kylo is conflicted, I mean…Rey is clearly conflicted about killing him too, so like…no. And also Rey wouldn’t have been conflicted at all if Palps had just let her kill him in the first place, and-and-…uuuuugggghhhhh. I haven’t thought about the finale in months and I was happier for it. Damn you, all lol.
I think GLogus’s idea has a lot of potential - you’d have to make it more that he wants Rey to join him as apprentice I think, otherwise you run into the same problems as before with the Dyad surprise. Then it’s like Anakin joining to save Padme, Rey joining to save her friends. But what would happen during the whole “She will draw her lightsaber” sequence? Would we just remove all of Palpatine’s dialogue?