Let's assume for the sake of this POD that Israel and Judah get smart kings/tribal leaders that decide to bow down to Assyria and Babylon, and are still in Canaan as independent kingdoms by the time of the Achaemenids. The POD is that the Jews are never deported and remain in Canaan by Babylon and Assyria. What happens?
Note-The United Monarchy and its existence or non-existence is irrelevant to this WI. The intelligence of the men running Israel and Judah, OTOH, is a big relevance.