To achieve scaling of bones while translating the Transform Constraint (TC) target without scaling the TC target itself, you can use a combination of transform constraints and possibly additional bones. Currently, Spine does not directly support converting translation to scale through a transform constraint. However, you can create a setup where a bone's scale is influenced by the position of another bone using indirect methods, such as using IK constraints with stretch enabled or by manually animating the scale based on the position of the TC target. This requires some creative rigging and animation techniques to simulate the desired effect.

bapho It is generally easier to use IK Constraints to create a rig in which a particular bone is scaled by the movement of a particular bone, by checking the Uniform option in the IK constraint and also checking the Compress and Stretch options. There is an animated GIF in the user guide that shows how this works: https://esotericsoftware.com/spine-ik-constraints#Uniform