Just spitballing here, but the biggest issue with Luke’s death is that it feels a bit random. Like, he could just as easily have lived, so it’s unclear what purpose his death serves.
So what if Luke saw his own death when he confronted Ben, a death he knew would take place on this island? This is hinted at when he says to Rey ‘I came to this island to die’. However, in that context it sounds like he has just given up and figures that this would be as good a place as any to spend the rest of his days, instead of accepting the truth of a vision that is put in motion when he fails to kill Ben.
Perhaps he says something in the Jedi Tree:
“I will never train another generation of Jedi. I came to this island to die…that is my destiny. It is time for the Jedi…to end.”
Just a bit to emphasize that he has seen his own future and believes it to be unchangeable. Therefore when he dies it is in fulfillment of his own vision, but interpreted in a hopeful way that he couldn’t have foreseen.
Dude!! That’s so good!