M-m-m, you pose interesting questions, but do it more or less vaguely
How do you mean, 'True as opposed to Fact'? What is 'true mythology'?
But since I reckon I follow you I would say there are no 'not true' mythologies at all, all are 'true'. But even if I fail to follow you, nevertheless my answer would be
yeah in both cases, that is, Ea is true mythology to me, and it is not opposed (per se) to Fact (still more Fact with capital F), it may be placed opposite it as a mirror reflecting it. All reflections in all mirrors are true in a sense they do reflect the Fact that is, but some may be 'truer' for doing it better, or maybe some may be 'truer' for certain types of persons who are attuned to perceive reflections seen in certain mirrors better than those of other mirrors. In that sense, Ea is true to me.
M-m-m, here I come out no less vague but even more so...