I don't think she is rooting against Ayano. I think she just doesn't think she can win.
What kind of dirty crap is that geezer pulling by promising Ayano that she can meet her mother, then ambushing her with a match, and telling her "win and you can meet your mother". The whole "win and you can meet her" angle is slimy enough, but then to tell her mother to leave the arena if Ayano wins, just completely takes the cake. He is trying to mentally break her.
At this point, I am not sure if Ayano's mother is devious, or just stupid and oblivious to her daughter's suffering.
The language of her grandparents' explanation for why Uchika left seemed vague to me. I can't tell if they were saying that Uchika left because she realized she was treating Ayano like a badminton player instead of her daughter. Or if they were saying that Uchika felt she was pampering Ayano too much, and she needed to leave her to help her become a better badminton player. All of the lead up to it with Ayano having trouble making friends and having a mental break over the loss, plus her coach's words about her mother not leaving because she lost makes me think, we are to believe she left to take pressure off of Ayano, but here she is in a scheme to apply pressure to Ayano.
The language from Kaoruko in this chapter indicates that Ayano's personality change is the opposite from the anime. She said that Ayano was a soulless robot before Uchika left, but now Ayano seems like a normal person. That would almost indicate that she has become a better person since her mother left, but it's hard to tell Uchika's motivations.
As for the other girls Uchika has trained, if she just wants Ayano to become a better player, maybe she trained them specifically as rivals for Ayano. That would be completely unfair to those other girls though, especially Connie who she basically adopted.
I want to think that Uchika's intentions are pure, but going along with this geezer who tells her "I won't let her meet you yet" is pretty despicable. Who the hell is this guy to get in between a mother and her daughter? What kind of mother is Uchika to allow herself to be bait dangled in front of her daughter's face and then yanked away?