Stormlight Archive by Brandon Sanderson. The whole series really. The overall theme is change/growth. The books are chonky, and that gives him the room to do what he does best: character work. There's a range of characters with a broad spectrum of personality types and issues, so it's easy to find something that you relate to. Main characters with depression, PTSD, complicated pasts. And while they do grow and improve, it's definitely more realistic than a lot of books I've read. It's not easy or a straight path to getting better, and sometimes they stumble. But the books do a great job of showing that those things are completely normal and part of personal growth. The people around them give them the support we all wish we had, giving a good model for how we can support those in our lives.

Just a couple quotes that have stuck with me for years:

From Words of Radiance: "Keep cutting away at those thorns, strong one, and make a path for the light."

From Oathbringer: "It’s terrible,” Wit said, stepping up beside her, “to have been hurt. It’s unfair, and awful, and horrid. But Shallan . . . it’s okay to live on." ... "Wit?” she asked. “I . . . I can’t do it. He smiled. “There are certain things I know, Shallan. This is one of them. You can. Find the balance. Accept the pain, but don’t accept that you deserved it.”