Appearently with the latest version of Lightroom the keyboard behaviour was changed (or I accidently found a hidden shortcut to change it).
Before, I was able to use the up/down arrow with a slider highlighted to change small increments (usually 1 step) and shift + arrow key to change large increments (usually 10 steps). Currently the arrow keys behave in the same way as the shift + arrow key (both doing large increments). Is this expected behaviour or a bug with the latest version of Lightroom? - if so, it's a terrible UX choice compared to the previous behaviour.
Might only apply to arm64 version on the new M1 Pro.
Restart and preference file reset didn't change the behaviour on my system.
Exposure behaves as you described on my system as well, but other settings (e.g. shadows/highlights, etc.) always increment in 10.0 steps (with and without shift key pressed). Previously without shift key pressed it was an increment of 1.0 and with shift 10.0