The problem is though, that the possession concept itself is shit. If killing Palpy allows him to possess you, the writers have created a no-win scenario. At that point, the only option for resolving anything is to gloss over the idea entirely. Rey decides that she’ll let Palpy take her over (because that will somehow allow her to control the fleet, even though Palpatine will be the one in control?), but then she senses Ben, and is like “Well shoot, what am I doing? This is a terrible idea!” But then as soon as Ben joins her, they’re about to kill him together anyway. And then Rey ends up killing Palpatine, but he doesn’t possess anyone. He just dies.

So you need Kylo to know about the spirit transfer in the beginning, as it gives a reason for not killing Palps immediately. But you also need Rey to not know about it, otherwise she won’t be so hard-set on confronting Palps. You could maybe try to ignore the possession thing entirely: “Strike me down, and your journey to the Dark Side will be complete,” just like in the Original Trilogy. But that still wouldn’t explain why Kylo lets him live in the beginning. And I would have a huge issue if Palpy set up this whole, stupid scheme - for the sole purpose of cloning himself and surviving beyond his death - if his entire subsequent plan is just “Kill me, Rey!”

I think it’s a sunk cost. The possession stuff is so messy and poorly handled that I don’t think there’s any way of fixing it. If someone has a legitimate suggestion for getting around it, then I’m all ears; but otherwise I think we’ll just have to accept it and move on.