At this point, not even a bittersweet, but the signature mean-spirited, cruel and spiteful Katsura special end.
Shinobu loses 2 girls and gets too traumatized he ends developing a fetish.
No romcom had done this shit with its MCs. Even Aitsu no Kanojo end gravitated towards bittersweet because MC at least had his kouhai by his side as some sort of life support (after the FeMC disappeared from his life, he fell into a spiral of despair and if not for the kouhai and her friend who decides to keep him constant company, he would have khs), but story was very specific about addictions, so in the end it was a kinda despair fueled end bc it's hinted Aitsu's MC would relapse into wanting to die if he reads that letter or picks that unknown caller call.
Even Boy's abyss, who, despite of the dark generational trauma, misery porn, dark side of the showbiz and adult world could manage to land a sorta happy end for the MC and the (ex),idol (and gravure junior idol & CP actress), even if he lost almost all of his ties with the people he grew with inside the town.