Back to basics:
Power is a function of torque times rotor RPM times a constant.
In this case, power is limited by TOT. Increasing rotor RPM will mean that you will have lower torque and a lower collective pitch setting. No more power going to the rotor.
Power is needed to overcome the drag on the blades, and lift is a useful byproduct.
You might have a lower blade pitch setting with the increased rotor RPM, but unless there's some significant reduction in CD with CL remaining the same or not going down the same amount you're not going to gain anything.