You are massively over-stating the significance of the connectome. We've had the complete connectome (and lineage) for C.Elegans, with a hundredth the neurons and a 25-thousandth the synapses of a fruit fly, for decades and getting animal behaviours to emerge from simulations of it is a field very much still in its infancy.

Edit: You're also massively under-stating the significance of individual cell behaviour. I expect "[h]uman neurons are ... [v]ery similar to those neurons found in a fruit fly" would draw hollow laughter from any cellular neuroscientist. Here's a random overview of a bunch of recent papers on the importance of cellular diversity in one small part of a mammal brain: https://www.frontiersin.org/journals/cellular-neuroscience/a...