For Mac: if you assign scripts (+ & -) wrapped in actions assigned to Fkeys, you can use a service like BetterTouchTool or Karabiner Elements to remap them for illustrator.
Bit of a workaround, but with BTT you're able to make essentially a virtual knob to do this if you have a track pad.
I'd suggest BTT and try it for a month, better UI than KE. KE is the free option though, but go BTT.
For Mac: if you assign scripts (+ & -) wrapped in actions assigned to Fkeys, you can use a service like BetterTouchTool or Karabiner Elements to remap them for illustrator.
Bit of a workaround, but with BTT you're able to make essentially a virtual knob to do this if you have a track pad.
I'd suggest BTT and try it for a month, better UI than KE. KE is the free option though, but go BTT.