Hey Hal, I’ll expand upon stuff regarding Rey’s arc…
A lot of people seem to misinterpret Rey’s arc in TLJ as forming her own path without relying on others, and that it is just about her being Rey Nobody. This is incorrect; her arc is about accepting that the belonging she seeks is not going to be her parents, and how she comes to terms with how her parents believed she was worthless, resulting in how she no longer cares about her parents.
Rey wants to feel loved by her parents, she refuses to accept the truth that they think she is worthless, that nobody is there to care for her.
There is a reason why Rey spent all of her years, waiting for them to come back. She has been lying to herself that she has some grand destiny which is why her parents left her, showing that they love her and care for her, that she is worth something, but however… she wants to know what that destiny exactly is. She has been lying to herself that if she had learned what her destiny was via finding out who her parents were, she would feel loved, since in this hypothetical scenario they abandoned her for an important reason, showing how much they care for her. But they don’t.
When Kylo Ren gaslights her, she finally learns to stop living this lie, to accept the truth that they weren’t significant people who had a reason to leave her, but rather insignificant people who didn’t have an important reason for leaving her behind, that they didn’t care about her nor love her. The truth that they hated her. That she is worthless.
The “place in this story,” itself, never really mattered to Rey. She only intended to use it as a way to justify her parents abandoning her so she’d feel loved. So she’d belong to them, similar to how Woody wants to belong to Andy in the Toy Story films. The reason she says to Luke that she “needs someone to show her, her place in all of this” is that she wants to find her importance only for the sole purpose of using it to justify her parents abandoning her, feeding the lie that they cared about her and believed that she was worth something so that lie would never die off, so she’d feel loved.
But Rey is wrong. This was the point. In TLJ, her arc isn’t about her being Nobody… as I stated, she learns to stop caring about her parents because of how they think she is worthless. They only used “nobody” was a way to drive home the point that Rey’s parents did not have a good reason to abandon her which would imply they did love her, but that they were bad people who abandoned her because they thought she was worthless.
And Rey being Palpatine’s granddaughter alone does not undermine her TLJ arc, but her parents being good people does, because it means that she stopped caring about her parents all for nothing. They should’ve had it so her parents abandon her because she is a Palpatine [furthering her belief that being a Palpatine inherently makes her worthless (which Luke debunks by bringing up Leia)], which would preserve her TLJ arc.