This manga is pathetically lacking in content per chapter and never talks about Mino’s horns. It’ a weak romance-sol manga that just happens to have a hot girl. Not Fbi-kun’s fault.
Yeah, manga feels like spinning it's wheels. Which isn't necessarily a bad thing except the only real reason to read it is the MC's friends and Mino. The MC himself who it focuses on his reactions and general shittiness actively detracts from the manga.