Although both Luke and Rey had similar visions of themselves falling to the dark side, Star Wars: The Rise of Skywalker fell short of capturing the same magic from Star Wars: The Empire Strikes Back. The Star Wars sequel trilogy had a clear narrative parallel with the original trilogy in Rey's efforts to evade the dark side and destroy the First Order despite the knowledge that her lineage is linked to the Sith, though she successfully defeats them and forges her own legacy as a Skywalker. However, Luke has a more cohesive inner transformation, as evidenced in his vision on Dagobah.
As a former Sith nexus, the planet Dagobah is a place that is known for its strong connection to the Force, especially the dark side. When Yoda visits it near the end of Star Wars: The Clone Wars, it shows him visions of the rise of Darth Sidious. Despite this frightening experience, the wise and powerful Yoda chooses to take up residence there and stay until Luke Skywalker arrives to take lessons from him. In order to toughen his spirit, Yoda commands Luke to enter the cave, intending to teach him that he must confront his own dark side so he can defeat it. Inside, Luke faces an illusion of Darth Vader, which he defeats and decapitates, only to see his own face inside the helmet. Similarly, Rey faces a dark side version of herself in Palpatine's secret chamber inside the second Death Star, who wields a hinged, double-bladed lightsaber and spiky teeth.
The main problem with Rey's vision is that it is too abrupt and, in hindsight, inconsequential. Indeed, Rey has to face her dark side after she realizes that she is a Palpatine, but the vision doesn't resonate with her deepest fears as much as it serves as a reminder that the Sith want her on their side. On the contrary, Luke is convinced to enter the Dagobah cave by his well-intentioned mentor as a way to find himself. When Luke asks Yoda what awaits inside the cave, Yoda responds: "Only what you take with you." Hence, Luke's vision represents his honest fear, underlined by the fact that he is about to face an actual dark version of himself — in the form of his own father.
The "Dark Rey" vision only makes Rey even more scared of the Sith than she already was, as the only temptation it offers her is a nice robe and an awesome lightsaber. In fact, Rey's biggest temptation to join the dark side of the Force comes from Kylo Ren, her romantic interest, and the other half of her Force dyad, rather than Palpatine, whom she lacks any reason to see as anything less than an enemy. Luke not only entered one of the most spiritual places in the galaxy but also the farthest depths of his unconscious, which revealed to him that the enemy was inside himself, not unlike the dark side that Anakin Skywalker succumbed to.
The biggest difference between Luke and Rey's visions is that the experience of Luke in the cave on Dagobah from Star Wars: The Empire Strikes Back is completely upfront, leaving him with nothing more than his own unconscious to deal with. This is a kind of conflict that permeates the most ancient myths and stories across all real-life cultures and eras. In its attempt to replicate the same magic, however, the Dark Rey vision from Star Wars: The Rise of Skywalker has little effect on Rey's character arc, as it is a pretty straightforward demonstration of what Rey logically would never want to become.
