How to remove Touchbar animations?
Not a solution to the problem, but small tip to quickly change brightness and volume without waiting for full animation to expand or holding fn key to switch to the buttons.

Just quickly swipe across the icon in the direction you wan't to change (to the left - decrease value / to the right - increase)

or

You can tap&amp;hold, and then swipe where you wanted (your finger should ended up being offset from where the knob is). In this case expanding animation will be played, but you save some time not needing to navigate to the knob or buttons