It's a bit different. Basically, in Kaguya-sama, he tried to teach certain love/life lessons to the audience. And when he started actually having those pay off, the Japanese audience threw tantrums that showed they hadn't absorbed anything he was trying to teach them and he seemed to actually...
I think it's written from a very genuine place, but also a very frustrated one. His ideas didn't get through in Kaguya-sama, because many readers had fallen in love with concepts he wanted to condemn and he'd taken too long to condemn harshly enough.
So yeah, so far this story has been feeling...
Well, it is abrupt and condescending, yes. Nanto reads as Aka's own self-insert to be understood by anyone familiar with the mentality here.
I don't really think any of this is about the characters. Seki, Mari, the whole lot of them, are extremely shallow. They're more literary devices to...
I think you have that backwards. Seki isn't the MC, he's the male lead, and plainly written with the thought in mind that the audience, and the author, is more like Nanto than like him. He basically just exists to be a popular cool guy, and show they aren't assholes but admirable.
Basically...
It's probably the more real experience for the kind of passive pure boy Aka's criticizing with this. The guy who steals their girl is more aggressive, but not a bad person.
To emphasize the fundamental issue with the FMC. Aka has a fixation on real love being different from how love is depicted in fiction. The idea that pure love doesn't exist, and trying to live by such expectations will lead to failure, is constantly repeated in Kaguya-sama.
Now, pay attention...
"Crappy luck" is an inadequate translation for 腐れ縁, which means "inescapable relationship". Have a nice day.
https://kotobank.jp/word/腐れ縁-483215
https://kotobank.jp/word/腐縁-2031289
https://dic.pixiv.net/a/腐れ縁
Mostly good, but some small issues. The "裏" in 裏主人公 and 裏ヒロイン doesn't mean "secret". It just means "other side", not unlike how "B-side" would be understood in English when there's something of a split narrative. Examples of 裏主人公 are Reiner from SnK and Sasuke from Naruto.
"ヤな奴" in Miko's...