JTA very much fits this category, though i do censor myself a bit, this story is very much adult.
The premise of 3 bros on a roadtrip sounds like common teen or even kids stuff... But JTA focus on a lot of the things you don't often get to see in those stories.
A lot of the story revolves around the mental health of the characters, how being a good person can often conflitc with doing what is right for you and how damaging that can be on a long term when you only think about others... BUt also the other way around, how not thinking of others can erode ones morals to the point where they don't feel like they fit in the world anymore.
The story is not nescessarily dark, but it deals with many, many shades of grey... And that is not even mentioning the naughtyness and violence of some of the scenes.
So if what i described above or below sounds like a fun read to you, check it out ^^
Journey to Ataraxia (JTA for short) is a furry/polyamarous/romance/drama/action/slice-of-lifeish story set in magic infused version of the roaring twenties that is ruled by dragons..
Our trio of protagonists meets each other on unlikely circumstances and decides to band together in order to find some semblance of peace, quiet and love on a world that seems completely determined to off them one way or another.