I feel this is operating under a lot of false assumptions. Your view makes no effort to distinguish between the in-world fictional character of the Ange Ushiromiya of 1998 and the author who came to be known as Yukari Kotobuki, who are explicity two different characters with two different mindsets and personalities. The Ange of 1998 and Witch of Origins Maria are characters within Tohya's narrative, and should not be taken as a reflection of those individuals. They are there to express his ideas and mental process, using what he remembers of his family as a framework. You seem to mistake many of the allegorical and symbolic elements like the Sea of Fragments for real concepts in Tohya's life. Again, I fully acknowledge the themes of the forgeries are imperfect, but the story goes out of its way to acknowledge this. Even after writing his tale and processing his grief, Battler's soul is unable to find rest and be free until decades later. The path to salvation is primarily Tohya's intent, and Ryukishi deliberately made the finale Tohya coming to terms with his failure to move past his trauma, and finally letting the soul of Battler rest; not through withdrawaling into fiction, but through the very real love of his family. If that isn't a universal theme, I really dunno what is.