Been some time since I last saw the film but it seemed to me that Luke put himself into a self-imposed exile.
If the others ever needed him, he trusted San Tekka and Artoo to know when and if to disclose his location. Separating the map ensured that it meant both of them agreed that he was really needed.
Yeap exactly this seems the most likely explanation, and is all but implied in the film. Will we get direct confirmation of this in the next films? If it’s important, sure. But it isn’t, necessarily.
Even though the question is left unanswered in the film, calling it a plot hole is kind of silly. A plot hole is an unanswered question that can’t be answered. This has plenty of possible explanations, from obvious to less so. Just because it isn’t spelled out doesn’t make it a “major plot hole.”
We need more scenes like the long sit-down exposition scenes in ROTJ and the PT.