Although she has been great actress thus far she was never as convincing with sisters as she is with JW... So you are right maybe it is RK who is motivating factor and brings the best out of her...
Also being relatively new and not as trained as RK and Ashwini are she may have reached her optimum and her new Avtar demands more then she can emote... It will take time for her to get out of old Bani routine and get into new role... She def needs a break and new direction to make the change and I am sure she will be able to pull it off once again...
I don't think there is a new BF in the picture , she seems to have crush on RK đ and spends her free time napping on the sets ..typical teenager I would say..
cheers.