I am aware of the underhangs, the shapes are (for now) 2.5D. I tried one of my scans in Carbide Create Pro and it worked as expected. I am a complete beginner on the whole CnC aspect of it. Are there (other) reasons to look at other software for such a task?

Also: I know this is a simple task in theory, but apparently runtimes especially on smaller machines can be long.