I'm going to join the choir and say all of the endings were disappointing in one way or another. I love the game, the setting, (and to a certain extent) the characters. I get that the devs were going for a dark, gritty and realistic game - but at some point it just felt like they were slapping more flaws onto characters and pushing more depressing aspects onto the game solely in an attempt to be "subversive" to what is usually expected from something marketed as an otome/vampire dating sim.
Otome is a genre that is usually plagued with love interest on protag rape? Let's make the protag feel like a rapist, instead. Otome protags are usually a magical fix all band-aid for all the love interests' problems? Let's make it so the protag can't improve a damn thing about their love interests' life, and arguably make it even worse. Otome game endings usually contain a multitude of happy endings, and unlockable ones that are even happier? Let's make every single ending a downer in some way - even the "special" ones they have to spend hours unlocking.
If I sound bitter it's because I am, the devs even said as much that they were aiming for this game to be an unforgettable experience, one unlike any other you'd played before - and it is, for all the wrong reasons. In hindsight it was also really cruel of them to "hype" the routes up as being '15' on a scale of being mature/shocking, and is what contributes to me feeling like they ended up shooting themselves, the game, and all the endings in the foot - all for the sake of being a "subversive" but ultimately unsatisfying experience for the people who played it.
I don't regret buying the game on the first day of release (despite how grating the ending bugs were) and this won't make me not support them in the future. Just wanted to vent what I feel are some reasonable criticisms of this game as a whole.