Okay, good, you got the definition right this time!
(Last time: "Solipsism states that all there are are the contents of my own personal mind." See the difference?)
Remember your miracle? "For me I start w/ that there are experiences and there are those who experience and affect other experiencers." (Emphasis mine.)
But your necessary precondition was less than that: "Qualitative experience is the primary for any knowledge whatsoever."
See how it doesn't include the bolded part?
Materialism doesn't deny your necessary precondition. It simply takes issue with your bolded miracle as being not parsimonious.
Prior to our vast accumulation of scientific knowledge, materialism also had to make a pretty sizable assumption.
But these days, it's down to basically, "There are experiences. Let's see what patterns we can find in them!"
Of course, strict materialism does have to assume more than that. But if you just start with experience, you get tentative materialism.
Even if you start with your miracle, materialism has a good showing unless the miracle also starts with a denial of various other things. For instance, you don't rule out that there could be non-experiencers in that miracle. "There are experiences, and there are those who experience and affect other experiencers, and nothing else" is an even more extraordinary miracle.
If you don't go that far, you notice some weird properties of your experiences. Some of your experiences seem to be of you-like things in that you get complex feedback from them. Some seem to be of dumb-as-a-post things--posts, for example--that seem to have practically no behavioral repertoire at all. If you haven't done "and nothing else", there's no particular reason to ascribe experience to a post. Furthermore, there seems to be a unity within experiencers that can be broken up to a point (e.g. one can lose their hand, and then they report a loss of experience from the hand, but still report other experiences)--and the disembodied hand then seems to be rather post-like and thus can be modeled as a non-experiential entity.
Working like this, you can come to a perfectly feasible model that has other experiencers as made from non-experiencing stuff, as long as you're content to not (at this point) know how you get experience out of non-experiencing stuff; and by analogy to them, you can conclude that you also are probably comprised of non-experiencing stuff.
So even with your miracle, you could end up with materialism as a perfectly reasonable hypothesis.
What you've done additionally is demand ontological primacy for experience (more miracle) so you can ground things in it safely. Otherwise solipsism would be a danger even given that you assumed other experiencers, because the problem of solipsism is not made any less acute if there is still a possibility that your experiences are not veridical.
The materialist again has less to assume; they can either assume a sufficient fraction of veridical experiences of whatever can be experienced (no pre-assumption that the whatever also has experience) so that they can detect non-veridical experiences, or they can decide that all statements will be "seems-like" and in reference only to their experience and not to any underlying reality.
--------
Low-stability systems favor truth because evolution is slow. If there is not a consistent position of a decision boundary, evolution can't find it. In that case, the evolutionary strategy is no strategy at all--all you can do is pick blind. So as long as truth is a better strategy than picking blind, truth wins. (I explained this last time, in slightly fewer words.)
--------
You say, "Neurons, just to give a quick example, have nothing about them that conveys the redness of red or the elation of listening to your favorite pieces of music."
Why are you so sure? There are certainly neurons in V1 that are strongly color-selective. Maybe the output of these neurons onto some others is identically the computation of "redness". How would you know that it's not?
Maybe it's the confluence of dopamine release with activity in the temporal lobe or occipital cortex that binds the recognition of music to elation and that input to somewhere or other is the elation of listening to your favorite pieces of music? Why not?
I'm not saying it's how it works because we don't know, but you seem to be supremely confident that no such answer could work. Why couldn't that be enough?
"It can't be that, because I've decided, sans evidence, that experience can't be a computation."?
You just state over and over and over that it's impossible, with no reasoning.