You've managed to scratch a mighty itch that's been bothering me for a long time. I finally have somewhat of a framework to think about it a little more, and I have you to thank for that.
In particular, this bit is pure gold:
> I think po-mo thinkers exist in a simulation founded on that base deception, and they try to convince others that their story (made of language!) is the substrate of our reality, but every time someone gets on a motorcycle, skis down a mountain, prevails over an MMA opponent, hunts food, rides a horse, jumps out of a plane, has sex for pleasure, or has some other peak human experience, the simulation disappears. All the neuroticism that forms the hall of mirrors of false equivalencies, evaporates, and what remains is gravity and time, the physical and the real, and our aesthetic experience of it.
Art is, at it's core, communication. More precisely, it's the name we've given to the wide variety of traditions that we've developed for communicating in manners distinct from plain everyday communication. Thus, art necessarily represents something, but each individual piece of art represents something different from the next. The message conveyed by a piece of art can indeed be to direct the recipient's attention to the technical skill of the artist, but in most cases skill is secondary, and only matters insofar as it aids the artist in communicating their actual intent.
As such, art which only exists to showcase the artist's skill is essentially devoid of meaning outside of vanity, such pieces of art representing something directly comparable to the significance of a sentence like "Don't you just love my accent?" - a self-referential display of conceit.
For this reason, I don't think you can really refute postmodernism simply by having some kind of direct experience of reality of the sort you were listing – as if postmodernists explicitly deny the primacy of these sorts of experiences. Postmodernists would only contend that a system of thought based on the primacy of such experiences is no more inherently valid or universally applicable than a system of thought with some other basis. (Though of course that is a very trite slogan, and I am not suggesting that all 'postmodern' thinkers would express things in those terms, or even agree at all.)
Understandably, people who don't like postmodern tendencies in thought want to find a definite definition of postmodernism to argue against. But as soon as you cast postmodernism as a particular doctrine that makes particular claims, it's no longer postmodernism.
This is a fairly widely mocked opinion, it;'s the same caliber of criticism as the "we should improve society" meme. The fact that both sides participate in shared narrative isn't a sign that both are corrupt, it's a sign the narrative is important.
https://knowyourmeme.com/memes/we-should-improve-society-som...
To take a toy example, consider the George Washington cherry tree myth: https://www.mountvernon.org/library/digitalhistory/digital-e...
I was taught that as a kid as a straight-up truth as a package of patriotic narratives. If I had said, "Well that's a good story, but that never happened," the people teaching it wouldn't have said, "You're right! But it's a good story that has a nice moral." They would have been mad at me for contradicting patriotic truth. And madder still if I asked why they were feeding me false stories as if they were true.
In contrast, the people I've read who would point out the issues with the cherry tree story are generally more frank about why they're doing it and more honest about the limits of knowledge and narrative. Many are happy to appreciate myths as myths, for example, and to have nuanced discussions about the role of myth.
I think we're seeing the consequences of this sort of postmodern thinking playing out "in the field" today. Everyone's an expert, so no one is. Everyone's an armchair epidemiologist. We aren't ignorant or ill-educated, we're "just asking questions".
There's something there that I can't put my finger on regarding the poisonous way we promise everyone that they can be anything. You, too, can earn $10k a month in your underwear via dropshipping. You, too, have the world's information at your fingertips, so nothing's keeping you from being an expert! You, too, can produce professional-quality video; all you need is the latest iPhone. And so on. I think it generates a lot of unspoken societal resentment towards people who are actually good at these things, because people who fail to reach that level of skill after 30 minutes are implicitly made to feel like they're doing something wrong.
I always use stubbing one's toe as an example of a direct experience of reality in all its realness.
(+1 to the favourable comments on your posts - complex ideas expressed skilfully and clearly!)
For example, two decades ago when I was double majoring in both geology and English, I found the poststructuralist idea that a 'text' exists separately from narratives about its meaning, but the narratives of meaning were inseparable from the broader social constructs use to build the narratives, both clearly correct and very useful in understanding the process of scientific inquiry. The Earth exists, you know, somewhat independently of us; however geological theory is a human construct and every part of the process from measurement to analysis to interpretation to presentation is a human act that carries with it the stamp of human ingenuity and human flaws: The sample sites selected for measurement, and the measurements themselves, contain biases and other uncertainties related to the selection process (mostly based on theoretical considerations), the engineering of the measurement tools, and other constraints (e.g. physical and budgetary limits). Obviously, scientific methodologies are centered around scientific theories, one or two of which is tested and refined in the process, but a thousand others are invoked as assumption and context, i.e. a larger theoretical structure. And presentation is communication, and additional choices are made as to what to highlight and what to gloss over.
Similarly, postmodernism's stance that there is no objective and unbiased observation and interpretation, and therefore all perspectives use one or more lenses that basically basically bias or filter the results, is clearly and often quite literally applicable to the sciences (think microscopy or remote sensing). Beyond those trivial cases, I think postmodernist theory helped me be able to disentangle the literature a bit and think, "OK, when someone interested in river erosion and landscape evolution looks at this dataset, they see X but I am interested in tectonics and Y stands out", or (in a wider theoretical context) "the geophysicists who come into the geosciences from physics use mathematical tools and make assumptions that assume the processes and configurations are time-invariant; on the other hand, the geologists know this area has evolved over the past 2 million years but their data analysis is trash--and that's why the groups can't talk to each other".
The major difference here I think is intentionality. The STEM communities do generally operate on good faith and have some sense of shared purpose, and scientific advancements are real, positive sum phenomena. So it's possible to apply these tools to the literature and to one's colleagues in a way that doesn't really involve value/moral judgements or seek to diminish or purposefully misinterpret the work of others. However this is missing in much of the liberal arts world where there is no clear definition of progress, and as a result much can be reduced to controlling unfalsifiable narratives and battles for influence.
That said, for all of its possible utility, critical theory's current escape from academia into the wider world doesn't seem to be going well. (For what it's worth, I also see modern Identitarianism as a full-throated but unwitting rejection of postmodernism, by holding that meaning is really implicit in texts, and that only some identity groups can legitimately produce and/or interpret texts. So they have moved on from Derrida's nihilism and are establishing a new priesthood even while canonizing him.)
Edit: I'd also like to emphasize that the ability to make somewhat accurate measurements, quantify misfits between modeled (i.e. theoretical) and observational data, and the ability to downweight, modify and/or reject hypotheses is also a major factor that allows for progress in STEM fields vs. the liberal arts, which limits the proliferation of bad-faith narratives that can use the offenses and defenses of post-(and post-post-)modernist theory.
The unspoken but founding lie of post-modernity is that criticism is equivalent to competence, and that critics are the equals of performers, but there's just all this false consciousness standing in the way that we can solve by indoctrinating people into narrative anyway. The whole enterprise is predicated on this original deception, and once you have accepted that, you can accept anything, which is why I think they teach it to undergrads.
The authenticity of "primitive" art as being a reaction to the skill and western artifice remains controversial, as if the art does not express the skill of the artist, what does it represent? Not everything has to represent something, but art is purely representation, so if it's not representing skill, there isn't a lot left.
There is certainly an anti-competence movement borne out of critical theories that need for competence to be isolated, as competence and risk are sources of truth themselves* and this physical truth competes with critical narrative, so on this, I don't know that it's a bridgable gulf.
This may be the most important part:
I think po-mo thinkers exist in a simulation founded on that base deception, and they try to convince others that their story (made of language!) is the substrate of our reality, but every time someone gets on a motorcycle, skis down a mountain, prevails over an MMA opponent, hunts food, rides a horse, jumps out of a plane, has sex for pleasure, or has some other peak human experience, the simulation disappears. All the neuroticism that forms the hall of mirrors of false equivalencies, evaporates, and what remains is gravity and time, the physical and the real, and our aesthetic experience of it.
That era has not ended, I'd argue criticism is just telling stories in a very shallow tide pool of history.