Shapeoko 5 Pro - Depth Issue

A Shapeoko 5 Pro would not need calibrating.

How deeply a given toolpath cuts will depend on where the origin is set relative to the surface of the stock and how flat the surface is, and how true that surface is to the plane of the movement of the machine.

I would suggest trying a test cut in a stable material such as MDF, first surfacing the stock, then cutting a test pattern such as: