For all we know Snoke was actually leftover clone bodies of Plagueis. And according to the movie, Plagueis is Palpatine. And all the Sith stretching back to Darth Bane. So really, the Rule of Two was a ploy that allowed Darth Bane to jump from body to body for a thousand years.
Did anyone else pick that up? Basically Sidious’ spirit was just possessing his own, mangled corpse. He wanted Rey to turn and kill him because that would allow him to possess Rey. It’s the same reason the Emperor was unafraid when he negged on Luke to kill him in ROTJ.
But when Rey refused, he used her and Ben’s Force bond to siphon their life force into himself and heal his own body.
Did I understand all of that correctly?
That’s a really interesting theory, though I can’t remember the film ever stating anything at all about Plagueis or any other Sith by name. I did get some Dark Empire vibes from the dialogue, and they did kind of imply that Palpatine is some kind of ancient being, so this could be canonized at some point. I do seem to recall though that the film implied that Palpatine was some kind of dark side convergence in the force, or even the embodiment of the dark side, implying that he too was born of it like Anakin was, but that’s a very vague implication that could go in any number of directions.