Luke was possibly a second try for the Force (which assumes some type of agency, but any of these theories do). Anakin met all the Chosen One criteria, except he turned (thanks to the Jedi Council and Palpatine's manipulations of them all). Luke was both a redemption for Anakin, a removal of the breaker of the prophecy (Palpatine), and a hope for the future. A second Chosen One, one who might be as or more powerful than Anakin in his prime, since he has the blood and gift but not Anakin's personal trauma that haunts and detracts him.

I think the biggest flaw of the sequels was the vagueness of why Luke couldn't renew or reimagine the Jedi again in a better form. It's glossed over to give a minimal backstory for Kylo, Snope is even more unclear and ended up being nothing, and why it drove Luke into isolation still isn't really told.

I liked TFA. I didn't like the start of TLJ. I expected a better thing that Luke just "meh" with the saber and the apathy towards everything. I wanted something deep and dramatic, tragic even. I was okay with Rey being no one special, that actually was the best part of TLJ (the end with the kid and broom). That seemed very interesting to follow.

Then it lost me fully.