Now sure if this is what you want, but for flying with rate you can find in stabilization settings max rate deg/s and change them from 250 to 1000 for example. This will allow faster flips, then you can enable Expo for pitch,roll,yaw (not throttle) which will make centre of stick more accurate/less aggressive towards full deflection stick being more aggressive in exponential scale.
So movements close to the center do very little, but as soon as your go closer to full stick deflection it would flip crazy fast. Maybe you should try it out