Going with the idea that the dagger was created by Palpatine, have Rey use that against him. Rey faces her fear, focuses in on the dagger’s origin, and uses that to get to Exegol (and leave coordinates for the Resistance to follow. That’s how you get around the lack of Wayfinders.
Nah, sorry, I can’t buy that. If Rey could use the dagger itself to find Exegol, they never would have gone to Endor in the first place. Remember, the dagger was made to guide the user to a Wayfinder. This is stated several times in the movie. Plus, there’s no indication she has it with her on Ahch-To. I think it got dropped somewhere on the Death Star wreckage? Not sure.
EDIT: Yeah, just checked the movie. The dagger was in her bag, which mysteriously disappears once Kylo appears in front of her. I’m assuming that in canon it was set on the ground in the destroyed throne room.