The focus should remain on Rey and not get too detailed about Luke. I don’t like him saying “I failed” in the present tense in TROS.

The existing line sets up his point well, in saying it’s what “kept him here” before Luke interrogates Rey’s misguided journey to that location.

I don’t know how to rephrase the existing line to retain the link to the location, lead naturally into a question of Rey’s fear, and change the implication about Luke.

In isolation, it wouldn’t be fair to characterize Luke’s reclusion to the island as due to straightforward fear. But in the context of the whole TROS Ach-To sequence, I don’t have a problem with this line. He’s making a point by picking up on a relevant factor from his own experience that mirrors Rey’s closely enough. Luke didn’t shut himself away due to fearing his raw power, but he did fear Ben’s. And perhaps that (but not only that) is enough to extend this question to her to relate and begin to pull her out of her slump.