I love the fact that you introduce the idea of story here, and raising it along with the question of what is truth is vital.
A central function of the ego is to take the facts of its existence and weave them into a narrative that provides it with purpose and meaning. A story is “true” in so far as it provides purpose and meaning, and “false” if it does not.
Obviously “true” and “false” in this context are necessarily subjective. Christianity is true for you in that it provides you with a compelling narrative that gives purpose and meaning to your life. Other religions are less true or perhaps even false in that their respective narratives are personally less compelling, purposeful, and meaningful.
In my own case, there is no one compelling religious narrative. There are parts of many religions that I find meaningful and which provide me with purpose, and I sew these together in a patchwork narrative that speaks to me, but not necessarily anyone else. The thread that holds my quilt together is panentheism, the notion that God is both source and substance of all reality.
The value of story is its gift of myth and metaphor. When you note that God speaks creation into being I assume you take this figuratively. God doesn’t “speak” the way you and I do, but there is something about the nature of speech that lent itself as a metaphor to the mystery the author of this passage of Torah was trying to articulate. Our job is not do defend a flat literalism that insists God has vocal cords and speaks Hebrew; our job is to explore the nature of speech to see what meaning we can glean from the metaphor.
For me the giving of the Ten Commandments is a story. The question I ask is not, “Did it happen as the Torah says,” but “What meaning can I find in the story itself.” In this we are in perfect agreement: “lay aside other matters, and listen to the story. Imagination may well be God's surest path to one's deepest self.”