>although I wouldn't say these ruined Japan and made it unmanly, but just the worst that is Western philosophy and values and how it made post-war Japan turn away from their manliness and dying with purpose.
This is very true. Like I touched on briefly, some Japanese thinkers were arguing that Buddhism had, by and large, been successfully sublimated in the Japanese kokutai / national polity. I think I would agree with this analysis as well, and it's actually essentially the analysis put forward in Kokutai no Hongi - an official work put out by the government on the core principles of Japan. There were many interpretations done by Japanese that successfully integrated Shinto and Buddhism to such an extent that many people would hardly know a difference between them in Japan. The period Japan from the beginning of the Meiji Era to 1945 was extremely masculine. Perhaps even the most masculine of the Axis Powers (and I say that with no disrespect to the Third Reich).
The problem they were identifying themselves was Western ideologies that preached individualism and societal disharmony
The sort of self-discipline and asceticism put forth in Buddhism is in my mind the pinnacle of masculine virtues, at least in its original forms. Mishima's analysis is seriously flawed, though exact usage of Buddhism put forth in his tetralogy works rather well, as it has reduced the character Honda to passivity, weakness and degeneracy compared to incarnations of the young men he came in contact with reached greatness. It might be a certain interpretation
of some kinds of Buddhists, rather than the teachings themselves.