A true story is a story that has actually happened in its essentials.
A  myth is a story that reflects unavoidable baseline realities.  For example, the myth of Persephone reflects the unyielding sway of the seasons.  Hot and cold, growth and harvest and fallow, year after year.

The Garden of Eden and the Fall is a true myth.

Most of its features are not arbitrary  narrative.  They represent the way things have to be.  There was “no other way.”

Here are some thoughts for you:

An overview of why there had to be commandments that had to be violated (sinfully or quasi-sinfully), why there had to be a Fall, why there had to be an atonement.

We want and fear significance, and we are right to do so on both counts.  (Bruce Charlton and also the JG).