Biblical and historical scholars think the evidence shows that the Hebrews were not monotheistic, but henotheistic, meaning they believed other gods existed, but theirs was the only one worthy of worship.
Alan T. Levenson, a professor of Hebrew history states that: “In the opinion of most Bible scholars, the ancient Israelites were monolaters or henotheists, who affirmed their allegiance to one God (YHVH), but acknowledged the presence of other gods for other nations. Not until a much later period… did Israel accept that God was one and omnipresent.”
“Archaeologists have turned up numerous statuettes of YHVS’s divine consort [wife] Asherah centuries after the prophet Amos had proclaimed Gods universal sovereignty. Synagogue services feature the verse from Exodus, “Who is like you among the gods, YHVH?” a question that makes more rhetorical sense if there are other gods, albeit false ones, with whom to compare the God of Israel.”