I have read the Genesis account and I did not get the impression of a "flat earth with a dome". I think you are reading other creation myths into the Genesis text. In fact, you betrayed as much when, in respect to what you claim as a proper understanding of the Genesis narrative, you stated that such could only be ascertained by "reading the original Hebrew and by reading contemporary texts of that time."
So I will pass on your particular brand of hermeneutics. I have no use for extrabiblical sources in that regard. As a Christian, I affirm not only the inerrancy of God's Word, but the sufficiency. In fact, anyone claiming to be a believer who does not hold to both the inerrancy and sufficiency of scripture should examine themselves, to see if they are in the faith.
If people change the translations of the original Hebrew and in many cases even omit hebrew words from their translations (which is common and I can show you if you're interested), then I'd say it's absolutely true that at least in these particular cases, we would miss the original meaning of God's word. Just like if someone changed the words and translating any other document. If someone wrote me a letter saying that they baked a chocolate cake, and it got translated into another language and the word chocolate was omitted, then the new reader would simply read that a cake of an unknown flavor was baked, and they could miss the original meaning.
I understand that God's word is for all times, but we can't be closed off to the possibility that our re-translations of scripture aren't always comparable to the original. Some translations I've scripture have been made for political reasons and reasons so that people can collect funds for their distributions. People make nutrients based on their sectarian biases etc. It should be of no surprise to any of us that in these translations, sometimes that original meaning can be lost.
In which case it's fair to go back to the original text for a more clear understanding of what was originally stated by God.
For example, if I say that in the beginning, God created the milky way Galaxy and the Global Planet earth, I would actually be changing what was originally said in God's word. Just like the Jehovah's Witness bible translation referring to "a god". If we change the translations, then It should be of no surprise to us that we won't find the original meaning. Or at least are unlikely to.
That's all I'm saying. And in this case, you're putting trust into modern translations, over original scripture, as it was written.
The historical accounts of other cultures, and scientific support backing the original Hebrew scripture, These are just supporting evidences for my position. I do not rely on them. They just back up my position. And they stand in contrast to your position.
This all goes back to my older point that if you have two interpretations that are conflicting, one of the easiest things you can do is look toward external details to corroborate your position.
And this is why it's actually good during Bible studies to read multiple translations of the same verse. Every individual translation is good if it can bring us closer to the Lord, but if we're really trying to figure out what a verse says, sitting around reading only one translation will often only get you so far, especially depending on the translation.
With that said:
A. I'm trusting in the literal and original Hebrew, whereas you're taking some sort of figurative or extra-"descriptive" interpretation of Genesis. It's unclear what that even means. Rather than taking the words at face value, you are suggesting that the Bible is using "descriptive" words that perhaps would help people understand things. So when God says that water had passed through windows of the firmament, in reality there are no such things as these windows or this firmament but rather God meant something else that is unclear. Rather than just taking scripture as it is written, you're starting to weigh in with some sort of subjective additions to it. And why you're doing that I don't really know. Do you have something to lose by accepting Genesis as it is literally written?
B. My position is backed up by historical accounts of every other culture of every other continent around the world. Your position doesn't have any of that. Despite part A, You're willing to hold your position even in the face of dozens of historical accounts that support my position and go against yours. Why? What do you have to lose that's so important that you would deny historical records as well? And it isn't reading history into Genesis, rather it's viewing context of Genesis which affirms what it literally says. Genesis says what it says, and the historical accounts are simply icing on the cake. The icing isn't making the cake but it certainly is supporting it.
C. My position is also backed by modern science which suggests that this deluge of Genesis was not global but rather was regional. Your position again doesn't have that. This one is easy for me because I also happen to be a geologist. My scientific observations as a geologist actually confirm what the book of Genesis is literally saying. Whereas your position is also contra to scientific observations as well.
Your position runs contrary to all three fronts, scripture, history, and science. But why? What do you stand to lose that you would stand in contrast to all three of these fronts, despite simultaneously not having scriptural support in suggesting the contrary (as described by Genesis, as per OT scholars such as in my linked article), despite not having historical accounts to the contrary (as described by historical accounts) and despite not having science to the contrary (as described by scientists).
The primary position is acquired through reading of the original literal hebrew text. The rest is just additional support.
And if you didn't get the impression that the firmament was a solid dome after reading Genesis, why do you think your interpretation is correct over anyone else's, in light of not having scripture, history or science which suggests otherwise?
Genesis doesn't describe the firmament being empty space or gas. It says it has windows and water above the windows. That has lights within it. So
why believe that Genesis doesn't mean what it says?