What possibly could Okonkwo and his life stand for, represent, or symbolize in this larger sense?

Consider the theme of greatness and ambition. Okonkwo is determined to be a lord of his clan. He rises from humble beginnings to a position of leadership, and he is a wealthy man. He is driven and determined, but his greatness comes from the same traits that are the source of his weaknesses. He is often too harsh with his family, and he is haunted by a fear of failure.