I always wonder how they think AGI is close when neuroscience is still scratching in the dark with brain scans, and we don’t know how digestion works 100% nor h

I always wonder how they think AGI is close when neuroscience is still scratching in the dark with brain scans, and we don’t know how digestion works 100% nor how to build a single cell in a lab then and have it skip millions of years in evolution to make a baby in 9 months. The AGI will definitely be different in structure than a human brain. Will it have a microbiome to influence its emotions and feelings?