So ends the manga. It's been largely forgettable because of the MC and the washboard, but dipped in to garbage territory because of the utterly stupid haircutCharacter Development™ in the epilogue.
Shirogane Mitsuha was the only interesting element of this story; everything else was a tired echo of what's been infesting anime and manga for decades now--with some of it being pushed as ideal for the sake of certain ideologues and sexual deviants (use your head here). The MC was attracted to a girl that who was actually the celebrity he was a massive fan of; not without cause, because--and it goes without saying--Shirogane's looks are part of Anima's appeal. He was into a girl with looks worthy of celebrity...and still found himself looking away from her to fidget over a shorthaired flatchest. Such a pointless love triangle was only added for pandering; doubly pointless because the flatchest obviously wasn't going to win (almost obviously: some authors defy even the titles of their works for this sort of pandering). Even at the end, he still permitted the flirting of that flatchest despite being in a relationship with Mitsuha.
Speaking of the end, Mitsuha was afflicted with the aforementioned Character Development™. It's a tired narrative element as well, one that few seem to understand the actual, surely unintended meaning of: women will cut their hair as if to "leave the past behind", or to symbolize their resolve to do something. But if they truly intended to leave such a past behind, or truly believed that what they wanted to do was worth doing, why would they need to cut their hair before doing so? Why not just do it? The truth, then, is that they didn't intend to leave their past behind, and didn't really care enough to do whatever it is they're pretending to be resolute about--they needed to whip themselves toward such actions first.
There's a reason why, when hairdressers would (in the past, anyway) see a distraught woman with long hair enter a salon and request a massive cut, they would refuse and direct her toward support instead. Even the flatchest, still hoping to play the homewrecker, suggested Mitsuha's cut was a product of heartbreak. There's also a reason why women would suggest that a beautiful, long-haired peer cut her hair--while keeping their own long in some cases. The reason for these is that it's a point of beauty--plenty of women will not respond well to having their hair touched without permission. In addition, there's a reason why such haircuts are called "bold" and "daring": they are actually ugly, signifying diminished femininity and feminine beauty, and to take such a cut despite what it almost certainly means for their appeal (not counting the attention of feminized males who, desperate to get in between thighs, believe what feminists said over the years; there are many such males today, and they even think their tastes aren't a product of social engineering) is indeed a bold and daring move.
You don't call a safe action that reliably produces good results "bold" and "daring"--it's obvious, then, that such cuts are inherently negative on a woman. And that's what Mitsuha was subjected to. Isn't it notable that Mitsuha's hair was bastardized to match the length of the hair of the flatchest the MC turned away from her for? Perhaps the author's saying something about girls who look like Mitsuha.