There’s a lot to like about this direction.
I wonder, however, if we can incorporate much of this idea simply by keeping Kylo’s offer vague. In the original speech he says they will kill Palpatine, but if it was left open ended, then he could be offering to run away with her and say to hell with Palpatine and the Jedi.
Since my current idea has the Sith dagger be something forged and planted by Palpatine purely to corrupt Rey, here’s what the dialogue could look like with that in mind:
“Rey….wherever you are…You are hard to find.
“You are hard to get rid of.”
“I pushed you in the desert because I needed to see it…I needed you to see it…who you are. Darkness is in your nature. Rey…”
“You’re lying.”
“You said your parents were nobody. But the dagger you found tells another story.”
“Don’t!”
“It revealed your parent’s fate. Are you still afraid to see it?”
“I don’t want this!”
“Search your memories!”
“No!”
“Remember them. See them!”
(Rey sees her parents protecting her, and their death)
“They paid for your protection…in more than one way.”
“Stop talking.”
“Rey…they were protecting you from Palpatine”
(Cutaway to heroes capture)
“I didn’t believe Palpatine either, when he told me who you were. He has lied to me for years…inside my head…in the voices of Vader…Snoke. But the dagger proved he was right…about who you really are.”
“No!”
(Vader’s mask falls to the ground)
“So that’s where you are.”
“You know why the Emperor’s always wanted you dead. I’ll come tell you.”
…
“Why did the Emperor come for me? Why did he want to kill a child? Tell me.”
“Because he saw what you would become. You don’t just have power. You have his power. You’re his granddaughter.”
“You know what you will find on Exegol, Rey. Darkness…or death. I made that same choice, once. But now we’re connected, by a power the Emperor cannot comprehend. Join me, and we can forge a new destiny…together.”
“You know what you need to do. You know.”
“I do.”
…
Now we get some of that recognition from Kylo that he’s been lied to, and that’s why he has no interest in following Palpatine or anyone else. The only reason that he believes Palpatine is because of the dagger, and in my concept this will be proven to be planted evidence.
This version even keeps the concept of Rey having the choice between the Dark Side or death on Exegol.