The Sun sets elsewhere

Hello, happy October! So I've just finished Osamu Dazai's book, The Setting Sun (henceforth referred to as TSS). I'd like to preface before I say anything that most of my interpretations are just that. Interpretations. Another thing is that I'm 15; I'm distant from adult life and even still I don't know adults quite like the adults in the book. Unsure if I got it right but enjoy anyways. Spoilers…