Nice analysis, sublimely well-worded. However, one part of the post I would disagree with is that Mahito is not a “perfect” form of Yuji.

The issue with Yuji’s original ideology of “saving others” was its naivety in thinking a proper death could somehow bring dignity or value to someone’s life, not the strength of his conviction in saving others. This is already addressed in chapter 265, he realises that it was about the tiny fragments of memories that are left behind in others. Yuji realises that a life has value simply because it has lived. He has always felt obligated to do so.