Why couldn't Rey trick Palpatine like so?

Question

In the climax of The Rise of Skywalker we have

Palpatine goading Rey into killing him, which would apparently "turn" Rey into the Dark Side. The Resistance fighters are also getting pummeled by the Final Order fleet.

What really bothered me while watching this is there seems to be a very easy and obvious way out of this dilemma. Were I Rey, what I would do is

Strike down Palpatine, assume command of the Sith, call off the Final Order fleet (thereby saving the Resistance) and then dismantle the Sith from within.

Heck maybe I'd even command the Final Order to just hold their fire and let The Resistance go to town on them.

Easy peasy lemon squeezy. Why couldn't Rey have done this instead?

The impression I get is that if and when Rey turns, she gets "brainwashed" and so could not act rationally, could not pull off this brilliant plan of mine. I find it very difficult to buy into this. For one, had Rey turned, her circumstances don't exactly put her in a bind; there aren't any Jedi Masters around about to arrest a Sith Lord and whose hand Rey can cut off, turning the tides. Also, if my little knowledge of Star Wars lore serves me right, turning to the Dark Side is more a switch of allegiance, of principles, and does not "brainwash" the Force user. So what gives?

Answer 1

From what I recall of the scene, Palpatine states that when she strikes him down, he and all of the past Sith will possess her, the act of killing him providing a conduit, and his knowledge and power allowing him to utterly crush her in the moment. This, of course, is the same thing that Palpatine tried to do with Luke.

Answer 2

First, Palpatine states that if she kills him, he will take control of her. Or at least that is a plausible interpretation.

PALPATINE: Kill me, and my spirit will pass to you. All the Sith live in me. You will be Empress. We will be one.

Possibly this requires the proper frame of mind, since Rey says that Palpatine wants her to hate him.

In any case, Rey is not about to risk this unless necessary.

In addition, the dark side does corrupt. That it is tempting is well known. Lashing out at one's enemy and killing them out of hatred is an excellent way to end up consumed by the dark side, considering that this helped lead to the fall of Anakin and Quinlan Vos, and almost made Luke give in to the dark side. And they didn't give in to the dark side on the literal planet of the Sith, which is probably a dark side nexus like no other. If Rey did what Anakin did, striking down a Sith Lord out of anger and hatred, her "journey to the dark side" would "be complete." Probably she would end up being an even worse Sith Lord than Palpatine, at least in terms of power, even if she escaped possession. Not immediately, of course, but soon enough.

Besides which, do you think the fleets of the Final Order would really listen to a well-known Resistance ally simply because she claimed to be a Sith, particularly after she killed their leader? They would suspect treachery, and Rey would probably have had have to prove it to them first, probably through actions that would be a quick path to the dark side. One presumes that if Palpatine had taken control of her that he would have had some means of establishing his identity, but if she somehow avoided that, she would be out of luck.