I had a similar relationship in the past that had a profound impact on me and I regret things that happened in it, but I moved on. Not being able to move on makes you way too dependent on the person you once loved to the extent it stops being love and obsessive. It's why I don't get that fluffy feeling others get from this story.
Sure that sucks but still that doesn't mean you can never move on in life, if you had a best friend as a kid who was forced to move away and stop being your friend does that mean you'll stop making friends ever? No. That's what I find weird about him.
It just seems like his life was pre and post her, especially now that he says that a relationship failed to him because it wasn't Kyou. That's just sad.
Yes, here's an interesting story search up Masahisa Fukase and see what happens when the woman you love becomes your obsessive muse. To me this seems like another mark in the whole his life was empty without her which is why I find this story tragic.
Perhaps that's fine but this doesn't read as a whimsical story to me because it reads as a man whose stuck in the past and lived a lonely life. The fact it could only be saved by his former lover who moved on basically coming back to save him is just sad to me.
For the woman's perspective sure, but again for the guy I just don't see it the same way. Hell he didn't even need a bunch of romantic relationships if he had a social circle of close friends, a super successful career as an artist or anything that made him look like he lived some sort of satisfying life after her I would have been more onboard with this being a happy story. I just don't see it that way it just seems like a melancholic story.
I'll just touch on the last portion specifically because it's the operative point.
You're not misreading the story. It
is melancholic, and I would argue you're viewing it correctly, at least to an extent. Takaharu is portrayed as a profoundly lonely man who never got over the most important person he had & then lost, and we're now seeing him struggle to make the most of the second chance he's been handed.
Other people seeing this as a cute love story that's full of whimsy isn't wrong, but that doesn't mean their interpretation is wholly accurate. I would argue this
is tragic, but it's also hopeful in the sense that, for these two people specifically, they've been given a second shot at happiness with one another, if only they can get over the past and their ongoing trauma and regrets and hangups to simply try.
It's grounded in the sense that the relationship they had and the dynamic between them now is nuanced and deep in how layered it is, but that doesn't mean it's not still a story that's working toward a happy ending that sees a "best case scenario" play out of otherwise rather dreary circumstances. As you said - you had a relationship that impacted you greatly and that you did at one point have regrets, but you moved on.
What if you hadn't? That "what if" is Takaharu, and this is the story of him trying to find the happiness that he's denied himself in being unable to let go.
Some people would uncharitably call it "wish fulfillment", but how many of us have some sort of regret that we, even if "over it"
now, don't occasionally think back and say "what if"? Stories are a way to play out that fantasy, and that's what this manga is. The art style is light and fluffy and whimsical, and I honestly argue it contrasts very nicely with the subdued pacing of the story and the often-times somber and pained notes in the interactions between Kyou and Takaharu. We can sympathise with what they're going through, because theirs is a relatable story that's taken to a narrative extreme for the sake of dramaticisation.
But while the themes are heavy on the regret and the stagnation in Takaharu's life, the intent is to see what becomes of the here-and-now, and what he can do with the sort of opportunity that I would bet many people wish they had a version of in their own lives.