If you accept the Garden of Eden version of creation, then you need to further examine the timescale involved. A long-past episode of inbreeding may not be of genetic consequence.
This is for one reason: whether you see it as divine guidance or not, nature (or DNA) only permits the survival of healthy specimens. The rest die. So continued inbreeding results in a smaller community, and over time a population that is too closely interbred dies out.
So if we are all descended from Adam and Eve, we've got away with it as we are healthy.
'Polluted bloodlines' is a telling phrase. We've all got bad apples in our ancestry, we just don't know about them. And utlitmately we are all related beacuse we are the same species.
We are told in the Bible that the menfolk mentioned along the way regularly bred with slaves they had acquired. So there's one pathway along which the gene pool diversified and remained healthy. It was usual in the ancient world for slaves to fit in with the cultures of their owners - so they and their children would become identified as 'part of the tribe'.
The events covered in the Bible were described in the words and concepts that were available to past cultures. But we now know that the timescale involved in human development is vaster than ever could be imagined by those ancient Jewish writers.
Many people of faith are prepared to interpret the Bible account as an extended metaphor, rather than an actual literal portrayal of events.