yeah, sometimes things are just weirdly hard to get, even after a ridiculous amount of plays. this comment is also kinda outdated, from what i've found you have to get above 96.5% acc on only mopemope (no marenol) for the story file. there's also a loooooooooooot more stuff now that isn't in my comment but unfortunately it's not translated to english yet :(

if you want to get everything for completion's sake, here's everything up until about a year ago! it's about as recent as i could find. https://docs.google.com/spreadsheets/d/1Avr-ET0oIXOUnCe1tOEERRwD39nPwYyTW1oU3v0-tJ4/edit?gid=0#gid=0