BBtBFWB

Not sure if it's here, but it's about two best friends (both girls). They were childhood friends that did everything the same as each other. Same hair, matching keychains, matching everything. Then, they started middle school (?) and MC didn't want to do it anymore. So, her "bestie" got angry and made the whole class turn against her. MC got new friends, but her "bestie" got them against her too (temporarily). Eventually, MC had a stable group of friends and they do fun stuff together, making the "bestie" jealous.

"Bestie"'s logic is, only she can be mc's friends and only she cares about mc. If MC does something which makes them not alike, then MC should be punished. She's crazy af and lowkey yandere for MC.

MC had a mop and short hair on the cover (her matching hair with "bestie" was long hair with bear-like buns).

There's also a classmate that MC kinda had a crush on, but "bestie" pretended to like him to get everyone to ship them together and make MC feel bad. MC doesn't really feel bad about it tho, since she's kinda friends with the boy. The boy's also one of her reasons to go against "bestie" in the first place, since talking with him made her realize that she didn't want to be a copy of her friend.

Manga where when you look at the cover it looks very melancholic, but the actual story isn't. It's about a guy who accidentally cuts his classmate's bangs.