You should read Nick Bostrom’s Superintelligence.

There are multiple theoretical paths to AGI, and one of them is “full brain emulation.”

This would essentially be scientists recreating a brain down to the neutron in electronic form. By its nature it would be faster than a human brain and could be expanded upon and improved.

I don’t know enough about the brain to say it will happen for sure, but obviously it’s an example of how there are different ways of achieving AGI that you may not have considered.