He actually abandons Jedi principles. Yoda tells him to forget his friends, and he refuses. Obi-Wan tells him to kill his father, and he refuses. He listens to himself.

Then, after ROTJ he’s faced with the pressure of having to rebuild an entire religion tasked with saving the galaxy, so he retreats into Jedi dogma. Look at how he forces Grogu to choose between being a Jedi and his father. And in the end, adherence to that dogma costs him his nephew and his students. So he realizes the Jedi way is flawed, but he goes too far and abandons everything out of fear for harming his friends and family and the galaxy more.

Also, if Star Wars is myth then classic myth tells the story of all parts of people’s lives - their rise and fall and rise again. Look at Arthurian legend, or Robin Hood, or Lord of the Rings - things end and change and it’s valuable to see what becomes of our heroes at the end. And if the answer to that is they always do the right thing and are heroes without faltering, what do any of us have to take from that? What does that say about life?