Looking for realistic, gritty, violent, uncompromising books with complex, morally-gray characters, ideally set in the modern age

Hello, first post here. It's been a while since a book has knocked me on my ass. I usually read non fiction and comic books. I would like to step into fiction, but I'm not sure where to start. I usually enjoy stories that are down to earth, violent, gritty and set in the modern-ish [...]