Having read Ingram's Mastering the Core Teachings of the Buddha (MCTB) clarified for me that key features on "path" are artifacts from persistently blocked info flows seekers are specifically advised to ignore. The description of 3 characteristics is clear enough for me to feel like I can articulate disagreement:
Suffering - or, Sure, Enlightenment is Great, but Have You Ever Tried Wiggling?
"Suffering" is just blocked motion. A practice where sitting still in a monastery wasn't such a central case wouldn't suffer from this confusion. We're trained to imagine that we can hold onto satisfaction by freezing. Nei Gong seems like a precise functional patch here. In Opening the Energy Gates of Your Body, Bruce Frantzis specifically talks about Zen masters going to Nei Gong experts to help them deal with problems caused by their practice.
Neigong is where you gradually build up Qigong / Taichi movements from the motor impulses you activate doing a standing body scan. The beginning of that process is especially important, learning how to do the body scan specifically for key nodes in your sensorimotor network. So, first you make sure your whole body can wiggle freely from a standing position, then you gently start instructing it to do stuff, only moving to the next step when you can do all the previous movements smoothly in a "wiggle freely" state.
I got legit value from trying out not wiggling for a while, to learn the difference between a desire to distract myself experienced as a desire to move, and an authentic motor impulse - but there are less coercive and more efficient ways to learn that.
Impermanence of sensation is conflated with nonexistence of noumena. This is just a problem of philosophical naïvete. Recommended reading: Plato's Theaetetus (I like the Sachs translation, Benardete is very precise but maybe too literal to read smoothly.)
Non-self is described clearly but with too little detail to be interesting, and suffers from philosophical naïvete. One might read The Opacity of Mind by Peter Carruthers, The Origin of Consciousness in the Breakdown of the Bicameral Mind by Julian Jaynes, and Prometheus Rising by Robert Anton Wilson for examples of what it looks like to pin this sort of thing down with specifics.
I have no reason to suspect that Dzogchen gets the wrong answer here (though I suspect it doesn't get much of a right answer either), except that Sam Harris thinks that he is much smarter than he is. So far my exposure to Dzogchen suggests that while they don't have all the answers explicitly, they tend to avoid faking.
When I read The Mind Illuminated (TMI) by Culadasa I felt acutely that it was a dangerous artifact in need of a clear warning label (though nowhere near as screamingly evil as the Bhagavad Gita, which I still think is worth reading for some people). I expect it to lead to results like the ones described in Clusters Of Individual Experiences Form A Continuum Of Persistent Non-Symbolic Experiences In Adults. Slate Star Codex summarizes:
When asked if they were stressed, they would say of course not, they were experiencing inner peace. But their friends and family said they were totally stressed.
See also Meditationstuff's critique, Mindfulness in Daily Life, Culadasa, the Dangers of Keeping Stuff Out of Consciousness.
The advice in MCTB seems likely to have similar side effects, which suggests to me that this is a general problem with received Buddhism. Basically received Buddhism seems to preferentially use sitting and concentration to narrow focus in order to make central insight easier, but in the process partitions a lot of psychosomatic information as irrelevant, which can lead to shifting problems into one's blind spots.
I'd expect a strong semi-active whole-body-movement integration practice to get rid of 90% of the risk, but I'd also expect a substantial chance that the two practices feel like they're at cross purposes, and that's a big extra time investment. If you understand this warning well enough that it feels intuitively obvious-in-hindsight that TMI's program could have those side effects, and it still seems to you like a good idea to continue the practice, then it's probably a good idea for you to continue the practice.
TMI has substantially tighter ideological closure than MCTB; Ingram encourages the reader to experiment, seek out other teachers, etc. Ingram also owns his perspective much better than Culadasa, and clearly warns the reader of the risks, so MCTB did not give me the strong feeling that a warning label was needed and lacking. It's the difference between a mad scientist saying "you can do this cool thing with this desired effect and these specific side effects, it totally works" and the CDC saying about the same intervention "you must do this thing, it's totally safe and reliable."