for the past two to three years I’ve felt like I’m a bad person even tho I’ve always wanted to be good. recommend me a book to characters who feels this.

since i was a child I always wanted to be this righteous, good person who doesn't do wrong by people but lately I don't feel like it.

I want to feel related to books characters who think they are a bad person, what should I read? I don't care if the ending is sad or happy, I just want to understand myself more through the eyes/thoughts of fictional characters.