Yeah, Obi-Wan and Yoda didn’t think there was still good in Vader. Luke did. And Luke was right.

I think proving his mentors wrong in ROTJ is the seed for where we find Luke in TLJ. Not the prequels.

Aside from a reference to Sidious, the prequel dogma is barely touched on in TLJ. The root of Luke’s disillusionment isn’t in celibacy, and the repression of emotion, humanity, or attachment. Nor in anything political. It’s in the idea that it’s “too late” for anyone. That’s straight out of ROTJ for me. It just wasn’t explored until this one.