Gura wanted to collab with Advent since the start.

But management wanted Advent to have a huge sense of unity within the group, stuff we didn't see in previous HoloEN gens.
So they instructed al the girls to act like a clique and shun other talents at first.
Gura sent a welcome to the advent girls before their debut, and they replied with a simple thumbs up.

Gura's autism saw it as: "we don't like you Gura! get out bitch!"

Gura would still be in the company, if management knew how to deal with people with autism.