Mc is a girl that is very smart and calm. She isn't treated very well by her parents because the neighbor is the typical reincarnated to a game who uses her knowledge of the game. I don't remember why but she loses her consciousness at a party and her parents don't care so a group of young people take her away and decide to adopt her. They are a group of friends both male and female that had noticed how mc was treated and decided to turn mc into their "little sister". The neighbor acted like she was bullied because she wanted to be adopted by mc's parents. She realized that she was in the world of a social otome game she played in her past life. She was investigated by someone from the group of friends and was caught talking about "hidden routes" and similar. The group of friends not only are from very important families, they are very talented.
Kinda sorta, the girl basically lived overseas away from her parents for a long while from what I remembered and the family that picked her up basically saved her from dying out on the streets. Her family basically disowned her.
Did a bit of digging to try and find this, due to it sounding interesting, and i think i found something that sounds like what you described. Haven't read it though, so i might be wrong. What i found is called "True Or False? ~ Love Game? No, I Will Not Participate In The Competition" on NUF. Would post a link, but this is my first post (I'm not active on forums usually) so i can't.