Wow, that’s a MASSIVE handful of straws you’ve got there.
What plothole? I see none. I don’t see what there was even any confusion about, as this is textbook Heroes Journey. Luke’s ultimate conflict in Jedi wasn’t about confronting the Emperor, his conflict was internal, and hey, you can’t have an internal battle of this nature WITHOUT temptation. Luke was tempted, but the entire point of the final battle is that Luke did NOT fall.
It also ignores the entire reason Luke surrendered himself to Vader in the first place:
Leia: But, why must you confront him?
Luke: Because, there is good in him. I’ve felt it. He won’t turn me over to the Emperor. I can save him. I can turn him back to the good side. I have to try.
The meaning of that final confrontation between Luke and Vader was the redemptive power of love.