“but if the premise is that there is a mythical component to the dogmas that waits to be discovered and discarded, then that premise is false by the definition of dogma”
Where did you get the premise that there “IS” a mythical compent? The goal is to see IF there is an error (which there generally is not).
To the extent you say never to test dogma (not sure you mean this), well, I disagree. Dogma should be tested early and often.
How do you propose we “test” any dogma? We either believe a historical fact took place or we don’t.