How to implement twin stick controls

Question

I am trying to implement twin stick controls in my 3rd person RPG game. The look and feel I am aiming for is similar to Ocotpath Traveler (2D sprites in a 3D world).

Right now my player character is structured like this:

KinematicBody
 -CollisionShape
 -Sprite3D
 -AnimationPlayer
 -Spatial
 --Camera
 -Spatial(attackRotation)
 --Sprite3D(AimIndicator)

And my code looks like this:

if Input.is_action_pressed("rotate_left"):
    attackRotation.rotate_y(deg2rad(3.5))

if Input.is_action_pressed("rotate_right"):
    attackRotation.rotate_y(deg2rad(-3.5))

But right now, it just rotates the indicator clockwise/counterclockwise when I tilt my right analog stick to the right/left. What I am trying to do is a more direct control. For example: When the player tilts the stick to the top-left, I want the indicator jump to the top-left of the character model.

How would you implement these kind of controls?