This one stands as a Litmus Test Shibboleth for all self-identifying Free Thinkers and Men of Science.
"Mythic" presumes that it may actually exist; "Mythical" presumes that it doesn't exist, nor could it possibly have any basis in fact or material realism.
Hence we do not need to look for it, because it won't be there.
Again, I stress "realism", over "reality", as it explicitly invokes the Thought Crime of Imagination and Creative Reason ("Logocentrism")
I am Logocentric and Proud.