I recently finished the junior novelization of The Last Jedi. It's worth reading both the regular and junior novelizations because they each include slightly different content, maybe different scenes or different looks into character motivation. This book made quite a point of showing the theme of failure--and then hinting at the connections between the different times of failures in the three plot lines of the story.
Finn and Rose go off to try and disable the First Order's tracker so that the Resistance can escape. They try and they fail and nearly get killed. Poe tries to reroute the Resistance to his rule by leading a mutiny against Holdo; he finds out in the end that he was wrong to not trust that she had a plan and that his actions have in fact destroyed that plan and allowed the First Order to nearly wipe them all out. Luke is trying to escape his failure to teach Ben Solo to be a good little Jedi and Rey is trying to reach out to Kylo and bring Ben back. Luke realizes that he shouldn't have just tried to leave it all and Rey realizes that bringing Ben back isn't so simple as just giving him the offer.
Everyone in this story fails. That's life; failure happens.
Finn and Rose's adventure is obviously connected to Poe's because Poe tries to take control of the Resistance in order to follow the plan the trio has made apart from Holdo's plan. But Rey's adventure is connected, too. She seeks something (a great teacher and helper) that she does not find and she goes after something that she does not achieve (the redemption of Kylo Ren).
Just the way that this junior novelization wrote everything out made me hear Rose's words about saving what we love versus killing what we hate in a new way. It made me think of everyone's attitudes towards Kylo/Ben. Luke and Leia have given up on him and don't think that he can be brought back. Rey thought that he could, only to find him still hanging on to his current path. But what if they're all going about it in the wrong way?
Don't kill what you hate (Kylo Ren). Save what you love (Ben Solo).
When Anakin Skywalker became Darth Vader, Anakin died and Vader took over. When Luke initiated Vader's redemption, Vader died and Anakin came back. What if the redemption of Kylo Ren happens differently?
Kylo says that Ben Solo was his old identity. The identity of Kylo Ren he created for himself; it was his way of separating himself from who his parents and his uncle tried to make him. It was his way of saying, this is who I am. I'm not the son whose father won't spend time with him. I'm not the son who can never live up to his mother's reputation. I'm not the nephew whose uncle fears him. I am all powerful. I can, not I can't.
So maybe, even though Kylo Ren is the representation of evil and wrong, just maybe there is something about his new identity that will linger. Ben Solo didn't feel comfortable trying to be Ben Solo. So he tried to be Kylo Ren and that only brought him more pain.
Maybe he will find the happy medium. After all, isn't he supposed to be the one who is composed to equal parts of the dark and light sides of the Force?
Kylo Ren won't become Ben Solo again. He will just accept that he is on the wrong path and readjust his path. Rey, in reaching out to him as he is, will say, I don't hate you, I care about you and I know you're better than this.
We fail when we ignore the fact that we can be wrong. We achieve when we remember our weaknesses and move forward despite them.