ethical, political and religious differences (which i’d mostly not place in the category of ‘priors’, e.g. at least ‘ethics’ is totally separate from priors aka beliefs about what is)

That's rather what I am saying. Although I would include "what is" as opposed to "what appears to be". There may well be fact/value gap, but there's also an appearance/reality gap. The epistemology you get from evolutionary argument only goes as far as the apparent. You are not going to die if you have interpreted the underlying nature or reality of a dangerous thing incorrectly -- you should drink water even if you think it's a fundamental element, you should avoid marshes even if you think fever is caused by bad smells.

are explained by different reasons (some also evolutionary, e.g. i guess it increased survival for not all humans to be the same), so this question is mostly orthogonal / not contradicting that human starting beliefs came from evolution.

But that isn't the point of the OP. The point of the OP is to address an epistemological problem, to show that our priors have some validity, because the evolutionary process that produced them would tend to produce truth seeking ones. It's epistemically pointless to say that we have some arbitrary starting point of no known validity -- as the already-in-motion argument in fact does

I don’t understand the next three lines in your comment.

The point is that an evolutionary process depends on feedback from what is directly observable and workable ("a process tuned to achieving directly observable practical results")...and that has limitations. It's not useless, but it doesn't solve every epistemological problem. (Ie. "non-obvious theoretical truth").

Truth and usefulness, reality and appearance are different

The usefulness cluster of concepts includes the ability to make predictions, as well as create technology. The truth cluster of concepts involves identification of the causes of perceptions, and offering explanations, not just predictions. The usefulness cluster corresponds to scientific instrumentalism , the truth cluster to scientific instrumentalism. The truth cluster corresponds to epistemological rationalism, the usefulness cluster to instrumental rationalism. Truth is correspondence to reality , which is not identical to the ability to make predictions. One can predict that the sun will rise, without knowing what the Sun really is. "Curve fitting" science is adequate to make predictions. Trial and error is adequate to come up with useful technologies. But other means are needed to find the underlying reality. One can't achieve convergence by "just using evidence" because the questions of what evidence is, and how to interpret it depends on one's episteme.