Modelling a twist like this procedurally I'm trying to achieve more or less this kind of twist on a model, but I want to do it procedurally rather than by hand. How would I go about this?
Picture for reference:

Thank you in advance!
As you suggested, you can use Simple Deform modifier for this

One modifier set to Twist for the spiral
Angle around 1080° for three twists, and use limits to move it up/down
Second modifier set to Taper, and adjust to your needs.