Post-Flood Diversity in the understanding of Yahweh
Coming out of the Flood, Noah taught about God, as did all his sons probably, and their wives. From Noah to Shem, Ham, and Japheth, spread the name and the way of Yahweh. Their traditions were passed down, as they always have been. However, as these people groups spread farther away—and through a multitude of events—so did the central understanding of Yahweh.
Which is why we see Joseph and the Egyptians in the same situation. It wasn’t God planting His ‘holy Joseph’ in a place of a bunch of “wicked heathen Egyptians.”
“For these studies [Genesis narratives] we want to understand the relationship that all these people — Egypt, Canaan, Ishmaelites, Midianites — had concerning the Creator God, Yahweh. People in Egypt used the name of God, Abimelech used the name of Yahweh.