I’d add that synapses are not the only game in town, and in fact neurons are only about HALF of the cells in our brain, the other half are glial cells of varying types. They perform a number of functions related to health, but also to the specific functions of individual and groups of neurons.
All of which is to say that 1015 synapses is just the start, and this is just the relatively gross micro-anatomy. The brain is unbelievably complex, and our understanding of it in depth is incredibly limited. The idea that we could accurately represent something we don’t understand, and that it would be a meaningful and useful representation, seems flawed to me.