There are plenty of films with a hard hitting agenda that playbthe gritty role you are looking for, but they are arguably all far more pastiche than Green Book. I just viewed It from a perspective of how a relationship could develop between 2 people from ‘supposedly’ conflicting cultures that turned into a life long friendship.
Watch The Hate You Give to satisfy your gritty needs - I think you might enjoy it (although it is a little pastiche 😂)