Hello, I'm looking for a manga, but I completely forgot about the title, but I remember I really enjoyed reading it.

What I remember about the manga is that the younger sister was really popular and seemed to have a brother complex.

She has 2 older siblings, her brother and her sister, who appears late in the manga. She definitely has more affection towards her brother and if I remember this right, she is kinda possessive of him. The brother wears glasses, likes big breasts, he is interested in the friend of his little sister, she got a ponytail and her sister is a gravure model.

The sister's friend seems to be interested in the friend of the brother and I think she couldn't really understand the sister's obsession with her brother. The little sister often checks on her brother with pretty much everything.

I'd really appreciate the help. Hope I didn't make it confusing.

Hello, I just wanted to announce that I finally found the manga I was looking for and discovered why i couldn't find when I was looking through the brother complex tag lol 🤣 It had no category tags at all. In case anyone was curious, I was looking for this
Nakahara-kun no Kahogo na Imouto