Your explanation of the situation is a little hard to understand. The etch primer is giving you an orange peel effect, or the 2k? The etch primer should go on just enough to put a bite in the metal, you don't paint the panel opaque with it. 2k always leaves an orange peel effect. You block sand until it is smooth.
When you sand through to the etch primer does your paper gum up? Or is everything dry and sanding nicely? If so, try adding a few more coats of 2K. You probably needed more coats of 2k.
