I'm curious how this isnt a seinen? The art style is reminiscent of a lot of seinen art styles I've seen (hell, even hentai, some of fmc's expressions look like they belong there), it has the common trope of an extremely beautiful tsundere fmc x utterly plain mc, it also includes the trope of another beautiful girl who will likely fall for plain mc bc he's not interested in her and become a love rival, and like you mention in your other comment, fmc's internal monologue entirely revolves around the mc. i feel if the genders were switched, it wouldn't be any question that it'd be a josei
It isn’t action oriented enough to me, and parodying other romances where the MC would be better off with anyone but the milquetoast guy she’s inexplicably interested in doesn’t feel aimed expressly at men. It doesn’t seem like seinen to me, I’d just call it a comedy, but if you want to call it that, be my guest.

This is neither harem nor seinen, I don’t know where they got that from.
At any rate, I started out disliking this and ended up liking it well enough by the end of the first volume. I really wish the translation wasn’t so half-assed, it DEFINITELY suffers because of it. From what remains in the English version, I bet there are most likely a ton of jokes that got steamrolled by the lack of even very basic translator notes outside of a couple of food names.
For an example of one of the jokes that remained that should have had an extended translation note but got nothing: “Cool Japan” was a real life program that was literally government funded propaganda aimed at giving Japan a cool image overseas (BTW, the program’s funding has since been significantly cut in the last few years). Joke-naming a fictional candy division of an actual government propaganda program (that was responsible for “policing” Japan’s overseas image) with the acronym “COP” is actually pretty clever on multiple levels, but since the translator never even mentioned WTF Cool Japan is, almost all of it would be missed by readers unfamiliar with the real-life program… which is apt to be most english readers. Come on, translator! You can do better!!
The English version so constantly reads as a missed opportunity for a better translation and localization, I’m half-tempted to seek out the raws. Even though there’s not much to this comic, I can’t help but be able to see that it deserved more care.