I think Palpatine’s plan was clear enough in that the audience never expects him to be trustworthy about what his true intentions are.
I’ve been thinking, in order to give some useful plot function to Rey’s vision, how about showing glimpses of Kylo Ren using the Wayfinder and going through the Nebula? I think this would motivate Rey checking out the Wayfinder on the book (if that’s still something that’s being kept), which then feeds into her showing Leia. Also it makes it so that when Rey gets the Wayfinder from Kylo’s Tie whisperer, she has at least already seen it there before and it doesn’t feel as much like it’s coming out of nowhere.