What I took out of RoS which I really liked the idea of was how it explained Palpatines “stike me down” lines both in RoS and return of the jedi. I like to think that meant that if Luke struck him down in return of the jedi with anger he would of possessed Luke the same way Rey would of been possessed if she stuck him down in RoS through the sith ritual.
I realize that doesn’t literally make a ton of sense given Palpatine’s ambition and ruling an empire, but it makes sense in the context of the morality tale that the original trilogy was. This added motivation means there’s a reason for Luke to resist temptation other than showing poise and maturity in the face of evil.
I think it can work both ways at the same time. Luke doesn’t know about the spirit transfer so he is still resisting darkness solely to not corrupt, while it’s also really cool from a lore perspective as a viewer. Plus like we’ve talked about it adds depth to Vader in this scene by knowing that the gears of redemption are continuing to turn for his son.