I've never found Dualism - the idea that the mind and the brain are two different substances with the mind being "immaterial" or "non-material" - a valid manner in which to address consciousness or any mysteries relating to it. To show the reasons why I think it's bad metaphysics I'll use analogous reasoning to make a case for my newly made up "mystic essence".
For hundreds of years scientists have studied plants and animals all across the world. But they still can't explain where ecosystems come from. They don't even know what ecosystems are. And there are several immaterial properties that ecosystems have that cannot be explained by the biology of plants and animals. For example; cooperation, coordination, interdependence and decomposition. A material world view cannot account for the existence of any of these things nor can it explain ecosystems so the best explanation is Mystic Essence.
I suppose anyone reading this will intuitively understand my argument is absurd. But let's take a moment and explore why it's absurd.
While the first sentence is certainly true the second one is not. We actually do know where ecosystems come from. They come from the interactions of plants and animals within an environment. The same is true of consciousness - we do know where it comes from. It comes from the electrochemical reactions of a physical brain.
The third sentence is also not true. We actually do know what ecosystems are. They are an emergent hierarchy of complex biological systems becoming more than the sum of any of their organisms. The same is true of consciousness. The whole brain has properties which none of it's individual neurons of pathways do.
The fourth and fifth sentence make the category error of claiming cooperation, coordination, interdependence and decomposition are immaterial - which they're not. They're conceptual. There's a huge difference. The same category error is often made when talking about thoughts, feelings, and reason.
And the last sentence is just an empty claim. It in no way explains how Mystic Essence can account for ecosystems nor does it show that Mystic Essence actually exists. The same is true of of those who try to use an "immaterial soul" to explain consciousness. It's not an explanation nor is it something that's been shown to exist. It's just a vacuous placeholder instead of a real answer.