A simple and little question about COD (please check!)

[Faucon]

I already had filtering at zero.

Remember, the problem is not the reaction of the plane. It's very very very very simple compared to all the stuffs you are explaining. It's just how fast the aileron will react to the action on the joystick. Btw this is something you can test on the ground.
Try to do 2 or 3 left-right rudder inputs in 1sec with your pedals (or any other axis), on the ground, and watch how the rudder of the aircraft react. The reaction is way too slow compare to your inputs.