If we are truly trying to "replace human at work" as the definition of an AGI, then shouldn't the engineering goal be to componentize the human body? If we could component-by-component replace any organ with synthetic ones ( and this is already possible to some degree e.g. hearing aids, neuralinks, pacemakers, artificial hearts ) then not only could we build compute out in such a way but we could also pull humanity forward and transcend these fallible and imminently mortal structures we inhabit. Now, should we from a moral perspective is a completely different question, one I don't have an answer to.

Not necessarily. For example, early attempts to make planes tried to imitate birds with flapping wings, but the vast majority of modern planes are fixed wing aircraft.

Imitating humans would be one way to do it, but it doesn't mean it's an ideal or efficient way to do it.

From the moment I understood the monolithic design of my flesh, it disgusted me.