I wonder if our understanding of ‘accurate’ is being used consistently. For example, Animal Farm is a story about talking farm animals. Talking farm animals do not exist and to that extent the story is “inaccurate”. On the other hand, its message about totalitarianism is widely accepted as true so that, insofar as totalitarianism is concerned, Animal Farm is famously “accurate”.
As for either of the Genesis creation stories, I am skeptical of claims that the ancient Hebrews reacted to these stories as if they reflected physical reality. Part of my skepticism arises from the nature of biblical Hebrew - a language that depends on symbolism and metaphor far more than the more semantically rich English or Greek. The ancient Hebrews, by virtue of their language, would be much more attuned to the use of symbolism than we do (a modern, post-enlightenment, English audience). My skepticism also is rooted in the structure of both stories, especially the first. It’s cadence, its majestic prose, its references to a figure-of-time so completely at odds with experience would have immediately signaled to the audience that here was a story whose meaning was symbolic, literary in nature, not factual.
With respect to your question - “how could [the ancient Hebrews] understand an inaccurate account”; the answer, it seems to me, is that they understood the creation stories as literary myths, not literal, historically accurate accounts. Nahun Sarna and Robert Alter explain better than I that the truths arising from allegory and metaphor are often more profound, richer and affecting than the mere recitation of history.
In other words, the ancient Hebrews understood the creation stories as metaphorical, not literal. And that, it seems to me, is the answer to your question.
Blessings,