My response to all this is mostly at the level of worldview. I don't have your confidence that I have the basics of reality sorted out... I could be dreaming; these consistencies might show themselves to be superficial or nonsensical if I awoke to a higher stage of lucidity... I'm also aware that there are limits to my own understanding of basic concepts like existence, cause, time and so forth, and that further progress here might not only change the way I feel about reality, but might reveal vast new tracts of existence I had not hitherto suspected.

I think I see what you're saying. However, I feel that hoping for ultimate realities undreamt-of hitherto is giving too much weight to one's own wishes for how the universe ought to be. There is no reason I can think of why the grand nature of reality has to be "richer" than physics (whatever that means). This reality, whether it inspires us or not, is where we find ourselves.

Now in general I am unimpressed (to say the least) with the specific materialistic accounts of subjectivity that materialists have to offer. So I think that the reflections of a typical materialist on how their feelings are really molecules, or whatever, are really groundless daydreams not much removed from a medieval astronomer thrilling to the thought of the celestial spheres. It's just you imagining how it works, and you're probably very wrong about the details.

Well now, I hope you were being facetious when you implied materialists believe that feelings are molecules. You are allowed to be unimpressed by materialist accounts of subjectivity, of course. However, you should seriously consider what kind of account would impress you. An account of subjectivity or consciousness or whatever is kind of like an explanation of a magic trick. It often leaves you with a feeling of "that can't be the real thing!"