I personally interpreted it as Luke being afraid that he would just make things worse if he were to get back involved.

When I was really depressed in the past, I would sometimes feel that the world would be a better place without me if I just didn’t exist. That’s why I really sympathized with Luke in TLJ. He was so guilt-ridden that I like to think he had a similar mindset that I’ve had before, and he extended that belief not only to himself, but the Jedi as a whole. He made such a terrible mistake that he wanted to close himself off from the world, because he didn’t want make more mistakes and hurt more people.

So I personally think the lines works. I just see it as, “It was fear that kept me here. Fear that I would just make things worse.”

And I kind of think Rey fears the same thing. She fears that she will just make things worse in the end. But she, like Luke, has to confront that fear of failure in order to help those who need it.

EDIT: Another thought. While it was a little flimsy, the idea that Leia abandoned her training because of fear (of the death of her son) ties into that theme in a way. Perhaps you could say Palpatine was responsible for the dark visions that Luke, Leia and Rey all have that led them to wanting to abandon the Jedi path. Because Palpatine is the physical manifestation of fear, and Rey defeating him is symbolic of Rey overcoming her own fear of failure. I think it fits Rey’s whole identity crisis pretty well, too. She starts doubting her own ability to become a Jedi, because she fears that she will fail, make mistakes and ultimately hurt people. But in the end, she learns from Luke and Leia’s failures and perseveres through her own insecurities to become a strong adult, ready to take on the world.

That is a very generous reading of the Sequel Trilogy, at least.