EOM:
The bible does not deny there are other gods. It only tries to say that jehovah is the god of israel because it was believed back then each peoples and tribes and nations all had their own gods. Gods powers only worked in Israel. We can see this belief in th example of Naman where he tries to carry back dirt from israel back to Syria( it hink twas syria) to help him with his leprosy. jesus himself never preaches to non jews for the same reason. Its as if each god has been allocated their place, and jesus mission is to guide them back to their rightful god. he doesnt try and convert gentiles because that would be wrong and upset the balance of the things.
The story of moses and aaron visiting pharoah is the same. The challenge of the snakes and shafts is about one god besting another. its never a qustion of other gods. We also have the challenge bewteen baal and jehovah on mt carmel.