How can I write a thesis statement based off of the theme of identity using the book The Moon and the Bonfire for evidence?

Cesare Pavese's novel addresses identity in several different ways, each of which could provide a substantial topic for an essay. As the narrator and protagonist dominates the action, it would make sense to use his story as the central focus. Bringing in one or two additional characters who offer complementary or contrasting situations would be a solid strategy. The novel is set in Italy, and most of the characters have remained there since the war's end. The narrator, however, left Italy and lived in America.
One primary emphasis that the author includes which could feature in a thesis is the importance of national identity. The narrator felt alienated and uprooted while living in America, which is one reason he returned to Italy. A thesis that argued for the centrality of national identity would be easy to support.
Another perspective could contrast the narrator to Nuto, who remained at home. A slightly different thesis would emphasize the importance of home or community on identity formation: e.g., rather than the experience of living abroad, it is the absence of community that shaped the narrator. A different character who offers a clear contrast is Valentino. Unlike Nuto, he has not benefited from the concept of community and has turned into a killer.
An effective thesis could argue that individual experiences, rather than social context, play a greater role in shaping identity.