I thought that by now there would be considerable posts in response to your critique of Dick's analysis. I guess it's all hidden.
Anyway, my thought is that much of what Dick identifies is correct, like the existence of the so-called pipeline of conscious and unconscious thinking and that everything can be represented by numbers.
I also think that he has presented a mathematical derivation that is worthy of consideration. For example, your consideration is that his relativistic predictions are incorrect. Not being expert in relativity, I will take your word for it, mainly because I prefer Einstein over Newton when it comes to relativity. So then we can ask if his symmetries are incorrect for relativistic motion or is there an error in the math or the math procedure. All that is rather conventional scientific thinking. Experimental falsification reflects back on the assumptions.
But what seems to be glossed over in all our discussions of Dick's work and his rhetoric is that it is inconsistent with the scientific method.
We all know the difference between being subjective and objective. Dick by his own intention is entirely subjective, claiming to only be concerned with the pipeline and its design. He admits that all pipelines are different, which is what makes them subjective. But he chooses a design that may or may not correspond to one pipeline. For sure not mine as I experience symmetries not included in his design. (A pipeline is how any particular subconscious and conscious works).
Now science, in different words, recognizes the existence of the pipeline and does its best to minimize its effects. That's called trying to be objective. That is why in science repeatability is so important. We are objective if our results are the same no matter what pipeline is used. That is our assurance that what we measure is dominated by the input to the pipeline and not the distortion introduced by the pipeline.
That is the scientific method that has allowed humans to develop experimental science, and on its basis, scientific theory and law.
Dick rejects that method by claiming that the pipeline dominates. So I would not label Dick as a crackpot. I would just say that he does not believe in the method of experimental science.