Until you deal with the fact that ALL the knowledge we have of the brain - as with all the knowledge we have of the universe - only comes to us through consciousness - everything you're saying assumes your conclusion.

Implicit in all you write is the unquestioned assumption that the brain is the source of consciousness. Long ago, William James pointed out that all neuroscientific discoveries are perfectly compatible with the idea that the brain (and the whole universe) only exists within consciousness (not human consciousness).

If you're not sure what this means, look up Bernardo Kastup's analytic idealism course on YouTube. Forget his philosophy which is hopelessly conflicted. His initial two videos, explaining agnosticism as the proper approach when we use the scientific method, is the best I've ever seen on this topic.