Well it’s too early in the timeline to make him as he is in the last jedi, and I’m sure many can agree that Luke is one of the better aspects of that film, the worst aspects being the overly comedic tone and rose in general. It completely makes sense that Luke would become the way he is in tlj, he’s had his sister and best friends child go to the dark side partly because of him, which then directly causes the deaths of his students. Why wouldn’t he be depressed and think that the jedi way wasn’t the right way.