A redactor would have inserted YHWH unless Ex 6:3 is not the usual translation we have in our English Bibles as
@dybmh tells us and which I have also heard from other sources.
But nobody knows anything about it being "after 6th century BC"
As I said things like the 2 creation stories it seems is just the way things were written in that time and there are examples given in the video and the other link.
But when it comes to those 2 stories, the 2nd is not even a creation story anyway, it is just a more detailed account of the creation of man. The other things created were just for the man, not as a first time God did it,,,,,,,,,,,,,, imo