to me the tragedy in Fox's Wedding is that at it's heart it's the system of patriarchal, misogynistic violence and abuse that plagues Ebisugaoka perpetuating without end. resigning to the system.
Kotoyuki's entire personal conflict revolves around that like everyone deep down he also yearns for freedom but has resigned himself to that patriarchal role feeling it can't be defied. that is not to say he does not love Hinako and she does not like him- but while he would not be the same as Kanta (a violent abusive drunk even if we learn it's... more complicated than it seems) at the end of the day his role is to be The Man and make all decisions, and regulate Hinako's existence to being The Woman for whom he will make all the decisions for without question. i think that's why the description of that ending is "Dolls are happiest when they are loved."
Hinako (all of her I think but especially Fox) does love him and wants to be his wife, but also in that route has zero of the understanding of what actually makes Kanta's and Kimie's relationship work off-screen. that's why i don't think it's all of a bad ending- they are two people deeply in love, but they are also two people who have completely submitted to becoming cogs in the cycle of abuse. they will almost certainly have children one day- and if they have a son he will be raised to fulfill that patriarchal role without question no matter how much it may hurt his wife no matter how much he may (or may not) care for her, and if they have a daughter she will be raised to be a submissive and demure housewife who will sacrifice all of her agency to her husband without question.
something that's really funny to me is there's a lot of JP art about Fox's Wedding that basically has Fox Hinako as the Shiromuku still kind of wearing the pants not afraid to whack Kotoyuki with her fox arm, and it's funny to me bc art good, but also every time i see it without fail I think about how if anything that basically sums up Kimie and Kanta more than anything and how their relationship actually works, and how Fox Hinako has none of that understanding. i don't think that's an intentional commentary that art is usually making but it's what i usually think about when it pops on my tl on twitter