I saved on every part of the game that has choices, even the door choices one, I tried to load and check every other choices as well, (because well I'm a let's player and curiosity is a curse.) After like doing every single perfect and loaded that save, after checking like just not winning or perfect winning just like the first two monsters. the one I loaded, supposedly everything perfectly won, just goes into neutral ending instead. And it also somehow carrythrough after I new game. If there's point system, supposedly then it should be 0, but I did
everything for the chance to get good or even true ending, like the same choices you said before.... all of the
endings just become neutral, despite the other one looks like supposedly going to be True End Route. (it also still had the Neutral Text on before the battle, about believing in friends.)
For the follow up edit of reply, well you can see here.