I think you have missed the point here.
Truth is objective.
The prodigal son did not exist. Logically, I fail to see this broader truth. In the very nature of the case, Genesis 1 cannot be strictly historical, in the normal sense of the word. Clearly no man was around to record the events. Even if God revealed it, to compress the creation of whole heavens and earth into 31 verses, clearly required selection of materials on a massive scale.