You are right Graham, there is not real clarity on this issue. My own understanding is that the Israelites were very susceptible to joining their fellow Canaanites in worshiping the gods of the land, Baal, Molech, Ashterah (I’m naming these from memory so probably have them wrong). Most communities or peoples of that time had a local god they believed was tied to their particular piece of the earth. There are many places where God warns them against the human-made gods such as the bull image of Baal. So I think the proscription about not worshiping other gods is not necessarily a recognition that there existed other gods. But, the Bible is perfectly clear in noting the widespread existence of other sentient beings that are not human. Some even came to earth creating Nephilim. In the book of Job theres is a heavenly council and Satan is part of that. All rather strange and intriguing things.

I do not think this detracts from the basic point that the Abrahamic religions innovated to some degree monotheism. There was the Egyptian experiment with monotheism of the one god Aten in the 14th century BCE but apparently that didn’t last beyond the one pharaoh that imposed it.