.
But we know that the “oral tradition” began after the return to the land. Guesswork most likely, since Moses got his version directly from Yehova at Sinai.
I sure wouldn’t mary my sister (if I had one).
“But we know that the “oral tradition” began after the return to the land.”
No, it was given to Moshe at Mt. Sinai.
But I concur there are major issues with it; the written versions are not clearly recorded, conflict, and were prepared much later.
Hence, the two reasonable camps.
Arguing in your favor, would be that the narrower interpretation (half-sibling) would help explain the problem with fertility, whereas Abraham had no problem conceiving with Hagar.