> Genesis wasn't written in 2000 BC and is hardly an accurate historical document.
Actually, it is unknown when Genesis was written, but the evidence is strong that Moses is the tradent behind it, if not its actual author. It is the consistent historical documentary record that Moses was the author (Joshua 8.31-32; 1 Ki. 2.3; 2 Ki. 14.6; 2 Chr. 23.18; 25.4; Ezra 3.2; 6.18; Neh. 3.1; Dan. 9.11, 13). The Jews and Samaritans of the 5th c. BC attributed all five books of the Torah to Moses. Recent computer analysis of the Pentateuch point to a single author:
* The 5 books recount a single story
* The 5 books share a central theme: the covenant and the land
* The 5 books share the theme of faith in YHWH
* The poetic texts of the 5 books suggest a single author
* The laws are purposefully arranged as a textual strategy (with the Golden Calf debacle at the center).
* The 5 books share the promise of a coming eschatological king
There is no competing theory through history (until modern secular skepticism) promoting a different author.
It is probably best to understand Moses as the authority whose words are represented in the 5 books, though he may have authored them as well. That Moses is the authority whose words are represented and that he was generating documents can be readily accepted. Moses was generating information (sermons, rulings, narratives) that would be considered important enough to preserve in written documents. Some undoubtedly would have been recorded in his time and under his supervision. Others may have been produced by later generations after some time of oral transmission. It matters neither how much material is in each category nor which portions are which; the authority derives from Moses and he is inseparable from the material.
There's every reason to believe what we know as Genesis came from the 1300s BC and was finalized sometimes before the 6th century.
> Genesis ... is hardly an accurate historical document.
There is nothing in Genesis that has been proved to be untrue. And, in contrast to your statement, the historical details in Genesis indicate that it accurately preserves information from the times it describes: The Early Bronze Age (2000-1500 BC), or about 1700 years earlier than the oldest surviving manuscripts of Genesis. It’s reasonable to believe that some of this information had changed or would no longer have been known during the exile, so there is credible reason to believe an early source of this information.
> Monotheism in Israel seems to emerge in the sixth and seventh centuries BC.
This is an impossible position to substantiate since (1) the shelf life of papyrus makes it implausible that we would be able to find documents as old as 600 BC, let alone 1300 BC. And therefore, it is quite impossible (at present) to put the books in chronological order by the date it was written. The compositional histories of most of the books of the OT are too complex for you to be able to have confidence in your statement. (Well, you can have confidence, but you can't support it.)
Monotheism was always part of Israelite theology. No passage anywhere in the OT conveys anything less than the uniqueness of YHWH, notwithstanding the penchant for modern interpreters to impose a whole battery of "history of religions" presuppositions. As I said in another post, there is no clear and definitive evidence of monotheism's origins, so you are taking stands that cannot be substantiated.
> Also far too early, what text are you dating to 1300 BC?
* The text of Genesis uses a pronoun for "she", which appears in the Torah as hiw' instead of the usual hi', which is a term distinctly known only to the 2nd millennium. Another example is the word young girl, spelled na'ar instead of na'ara (the feminine form). It would be like us spelling the way Wm. Shakespeare did, or actually more like the author of Beowulf.
* The text and details of Genesis 14 have been analyzed to be from an ancient, non-Israelite source, but with an uncanny accuracy to what we (in the 21st century) know of history. The geographic details and language form speak to a text from the 2nd millennium BC.
* There are parts of the Book of the Covenant (Ex. 21-23), according to Brevard Childs, that reflect the antiquity of the text. "During the era of form criticism, this text was originally assigned to J, while others attempted to assign it to E. Since then, a growing consensus has emerged that the Book of the Covenant is an older collection of laws that are independent of and preceding the usual critical sources. ... All of these indicate a historical setting for this section prior to the rise of the monarchy."
* Some spelling and grammar from Genesis are from much later than the 13th c. BC, but the age of the present form doesn't determine the age of its contents. Modernizing works was common in the ancient Near East.
* The absence of Aramaic, Persian, or Greek influences in the grammar and vocabulary of the sort visible in the books that are dated by obvious criteria after the Babylonian Exile (6th c. BC) makes it likely that the Genesis text is earlier than 6th c. BC.
* As I already mentioned, the historical details in Genesis indicates that it preserves accurate historical information from the eras it describes.
* Every source of evidence we actually have points to Moses as the author (starting at Deut. 31.24), as if at least a body of work was written rather than merely passed on orally from its historical context of roughly 1300 BC.