Changing Play Rate of animation does not change the play rate

I have some aiming animations on the left of the picture that I want to slow down when you hit the aim button, and then speed up when the button is released. I just want their speed to go from normal (1) to extremely slow (.1)
I am trying to adjust the play rate from 0 to 1 but it makes absolutely no difference at all, I found if I set it to 10 then the animation is sped up a lot, I just can’t seem to slow it down at all.


I also tried changing the play rate bias but that didn’t make a difference either.

I have the same problem, do you find a solution ?