Nev, was thinking about your idea, and I had this thought.
During the Resistance briefing, you could change C-3PO’s line from this:
Exegol does not appear on any star chart, but Legend describes it as the hidden world of the Sith.
To this:
A lost Sith world. Legend says the Throne of Exegol held the power over death itself.
This actually would be the perfect place to put this type of exposition. This is the scene where we get the Palpatine exposition dump, with our characters speculating (and us wondering) on how he’s alive.
With this line, we are told why this place is important, and what’s special about this place that allowed Palpatine to survive. Also, it is the antithesis of the Dyad in the Force. The Dyad has the power of life itself, the Throne has the power of death. Only one person can sit on the throne, representing selfishness. But the Dyad is two that are one, representing selflessness. The Dyad is a human/spiritual connection, the Throne is a material/physical connection. Love vs Power.
So I wouldn’t interpret Palpatine as “alive” until he absorbs the dyad energy. Up until then, he is just “undead”. A Sith lich.
It would work with the theatrical since the throne is destroyed in the explosion, but all you would need to do at the end is just add more lightning VFX that go past/through Palpatine and hit the throne. And make sure it is depicted so Palpatine is shooting lightning the whole time up until the throne is destroyed, so all Rey is doing is deflecting/redirecting it.
And if you wanted to use Jedi voices to remind the audience, it could be something simple like, “The throne, Rey.” You could also make the Jedi voices give just random pieces of vague Jedi wisdom, like Yoda’s knowledge and defense line, but allows us to connect the dots that adds up to this conclusion. I like the idea of this moment being generally inspiring and carry a more personal character/story-driven message, but maybe it can be framed in a way that kills two birds with one stone.
Honestly I think this would be a really satisfying way to address how Palpatine won’t just come back again. And even better, Rey uses her wisdom to realize how she can defeat Palpatine without just straight up killing him up, which it currently seems like she does.