https://en.m.wikipedia.org/wiki/Philosophical_zombie
Hard to think how we could approach this scientifically, but I think most people would treat it as a truth that we're all conscious.
But importantly, what physical detail about consciousness could possibly be the case such that it would not be accessible to a scientific endeavor. It's physically embodied and implemented by the rules the universe seems to obey, right? And if not, why not? Is it accessible through mystical methods which are non-scientific?
I believe we can study consciousness scientifically, even if our observations are limited to asking people what they experience, and making the grand assumption that the person is conscious (not a philosophical zombie). But the science may be limited by what is technologically possible.
As for something that may not be accessible to scientific endeavour: qualia. How can you know that what I perceive as the color red is the same as what you perceive as the color red? Maybe my red is your blue. Maybe my red is unlike anything you've ever experienced. How can we possibly know?
In terms of consciousness, so far the best we have are some indirect metrics; see the neural correlates of consciousness for some of the best scientific discussion. But as far as I can tell, most scientists simply treat consciousness as a phenomenon, and don't worry too much about the philosophical side.
Ultimately my point is: is there something mystical that is simply not addressable by science, and from the perspective of (most) modern scientists, nothing about the brain is mystical, it's just a bag of stuff that does some stuff.
There's new evidence to support the idea of quantum effects in the brain. Far from conclusive, but it does give a little credibility to the idea.
There's also a hypothesis that the electromagnetic field produced by the brain could be the "carrier of conscious experience", which would at least solve the binding problem.
But you're very hand wavy and simply disregard my examples. Instead, you throw around the word "mystical" without giving a clear definition, which makes it too easy for you to move the goal post. And then you simply refer to the brain as a "bag of stuff", which is a gross oversimplification.