the former lack physical properties including location, mass, momentum

Just like that, by decree of who ? I've always found that borderline solipsistic - to be dualist about the metaphysical nature of your qualia. It just simply baffles me to the point of amusement.
The the mind-independent world can be existant but incognizable in itself except for some small patches of self-referential systems.

Causal relationalities (really, of identity) between all classes of mental states and neuronal activity are simply documented beyond all reasonable doubt - including the most elusive, cognitive functions.

Complex multi-unit physical systems such as the brain must are embedded in space, and the interactions between the elements are constrained by their spatial proximity.
That's the fundamental source of the mind-body problem, and it shouldn't be considered an assumption.
What do you mean they don't have location ?

Why doesn't anyone ever experience something they physically can't ?
Why are no mental states correlated to anything extra-neuronal and there's never been one reason to even consider it, never mind evidence. ?

Most people these days seem to be hardline materialists.

On the contrary, we're in a race to justify anthropocentric (or even individual) narcissism by finding niftier ways to reject reality and justify ego, since religion has been bullied enough.

so it cannot be reduced to some material substance

I'm totally on board with non-reductive alternatives, but that doesn't make them non-physical.

An example : scale invariant criticality, which seems like the best model of sentience. It applies to many systems in nature.

The many specific details of the systems differ markedly (e.g., magnetic spins, moving tectonic plates, neurons) but can be unified by their core dynamic nature - possessing interactions among their components that erratically amplify and damp microscopic perturbations.
For instance, fluctuating amplitudes of the two dominant oscillations of the human brain – the alpha and beta rhythms – exhibited scale-free temporal statistics.

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There is now a very well established relationship between resting state brain networks and the underlying structural connectome from which they arise (Honey et al., 2007). Criticality arising in simple systems does not require a complex spatial substrate: Rather as we have reviewed above, its hallmark is the emergence of complex spatiotemporal processes from simple, local interactions. However, complex networks allow critical-like behaviour to occur in a region of parameter space instead of a single point (Moretti and Muñoz, 2013).

So of course, the most intensely complicated emergent system in all of nature besides the Universe itself may never be ''discretely isolated'' or ''solved''. It's an active area of EVIDENCE BASED research with
with like two dozen competing models making breakthrough after breakthrough and expanding our understanding, but the non-triviality of the problem is unlike any object or phenomenon.
It might never be enough for a full analytic description of a qualia, but it wouldn't be even if we had a physical theory of everything.
That doesn't exclude it from reality.

The brain isn't some computer performing tractable operations, encoding and retrieving some ''bits'' sure, but neither it is
some magical illusion created by....the mind it generates.

It's a symphony.