I've noticed alot of Gyaru x loser/lonely guy/Otaku hit the wall HARD once the characters get together. They either struggle to progress the story cuz the main interest (the "will they, wont they") has ended or they just start introducing random tropes that make no sense regressing the characters back to their previous form or straight up abuse for no reason (if you know, you know)
I've only seen 2 mangas that haven't had this issue cuz shocker, the main character gets character development. That being Gals cant be kind to Otaku & Dont toy with me miss Nagatoro.