Maybe I'm just tired but I'm not understand your logic of -0.2 is the minimum and max is -1.0
-1 is less than -0.20
You're suggesting I invert it and set the max to -1 and min to -0.2, that to me makes no sense at all.
Max is on the right side, min on the left. Max is the biggest, -0.2 is bigger than -1.0... The user does not see the value, that's the default behavior with the Slider so it's not bad UX, these are the values I want