I believe you are incorrect. The parables are not myths. They are instructional fictional stories to teach a moral lesson.
Adam and Eve is not a mythical story but an account of what happened by God.
No, there is no reason to think that parables are stories based upon reality. And you appear not to be a Christian according to your own standards:
11 He replied, “Because the knowledge of the secrets of the kingdom of heaven but not to them. 12 Whoever has will be given more, and they will have an abundance. Whoever does not have, even what they have will be taken from them. 13 This is why I speak to them in parables:
“Though seeing, they do not see;
though hearing, they do not hear or understand.
14 In them is fulfilled the prophecy of Isaiah:
“‘You will be ever hearing but never understanding;
you will be ever seeing but never perceiving.
15 For this people’s heart has become calloused;
they hardly hear with their ears,
and they have closed their eyes.
Otherwise they might see with their eyes,
hear with their ears,
understand with their hearts
and turn, and I would heal them.’
Also we know that there never were only two people. How does that fit in with the Adam and Eve myth?
EDIT: My apologies. You seemed to take unjust loathing of the term "myth". Myths are often fictional instructional stories. Just what you claimed the parables to be