Enola literally had no flaws, no purpose whatsoever in the story, thus having no growth, no character arc, making for an extremely boring character. That's the case for Mulan too and Hollywood hasn't learnt their lesson.

But I must admit, that's the only flaw of the movie. Millie's performance is good, making the movie watchable at the very least. Set design, wardrobe and cinematography were great, everything else went right except for Enola's character development.