You'll never get a fundamentalist to admit to the documentary hypothesis.
But let's try.
Blitz - if Genesis 1-2 is a single document, why does the writer
consistently refer to God as "Elohim" in the first creation account, and, again consistently, as "YHWH Elohim" in the second? Sure, I might refer to Jesus as "Our Lord" in one place, "The Lord Jesus Christ" in another, and "Jesus" elsewhere, but there is no consistency to it the way there is in Genesis 1/2.
Interestingly, there is one reference to God as "Elohim" in Genesis 2 - the bit right at the beginning that actually logically belongs with Genesis 1.