Start shift and mouse drag WHILE swiping

I'm a musician using Bitwig Studio. I want to be able to use the trackpad to control the knobs in Bitwig which are controlled by clicking and dragging the mouse up and down. Holding shift allows for more fine tuning.

I'm getting a magic mouse soon so looking for a solution for that as well as trackpad.

On the magic mouse, 2 finger swiping up/down is fine.

On the trackpad, would be nice to have one finger swiping but don't see an option for that, is that possible?

Anyway, for both of them, what my issue is:

  • When I make a 2 finger swipe trigger a mouse drag and shift key down, it simply activates the mouse drag and shift key but doesn't move my mouse. I have tried using the trigger "left-click" but that also just clicks the mouse and then the mouse doesn't move.
  • What I need instead is, I swipe up or down on the trackpad/magic mouse and it holds down the mouse and the shift key and moves the mouse up and down as I swipe on the trackpad

Another way to explain this is, currently without BTT I can click and hold the trackpad and move up and down to control the knobs on Bitwig. But I want to be able to not have to click and hold, just to swipe.

Thanks alot

EDIT: I found a solution that exists on mac already, which is in accessibility to go to pointer control -> trackpad options -> dragging style -> three finger drag

Simply putting 3 fingers on the trackpad and only sliding my index finger works perfectly. Only thing missing is the holding down of the shift key.