Was Moses a monotheist?

Hello Rabbi,
In Parashat Shemot, Moses asks about the name of God:

And Moses said unto God, Behold, I come unto the children of Israel, and say unto them, The God of your fathers hath sent me unto you; and they shall tell me what is his name, and what shall I say unto them. 34 And God said unto Moses, I AM THAT I AM; and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you. 3:15 And God said again unto Moses, Thus shalt thou say unto the children of Israel, The LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations.

At first glance, the question is puzzling, since what does it matter what the name of God is if He is the only God who created the world (as you often say, “As for me, you shall call him Yankela”). And God’s answer is also puzzling, since I would have expected Him to answer Moses by telling the Israelites that the only God who created the world is the one who sent me to you. And indeed, I saw in the Keter Yonatan translation that he translated the phrase “I will be what I will be” as follows: “He who said and the world was, said and everything was” (meaning that he also felt the difficulty here). But if you read the text from a polytheistic perspective, both the question and the answer become logical again. In a polytheistic world, the question of which god sent Moses is of great importance, and the signifier of that god is his name.
It is possible that in the time of Moses the issue of monotheism was unknown (at least according to one of the sources J, E, P), and it only developed in a later period among the people of Israel. This also relates to another question I asked you regarding the verse in the inheritance of the highest nations, when He separated the children of Adam, He would set the boundaries of the peoples according to the number of the children of Israel/God. And regarding what you wrote to me there: “If the Holy One revealed Himself to Abraham, then I assume that he knew who was speaking to him,” I think it is not necessary that if the Holy One reveals Himself to someone, then He will also inform him about matters of correct theological perception. Moreover, it is possible that such an update would not be acceptable to the Israelites and perhaps even Moses and Abraham, since the story of the Egyptian pharaoh Akhenaten is well-known, who tried to uproot the concept of polytheism from Egypt and transfer them to the worship of a single god (for example, he made sure to erase the letters “Yam” wherever it says “Gods” in various temples), and he was unable to do so. Not only that, the Egyptians tried to uproot his memory from the Egyptian chronicles following this attempt (which they ultimately failed to do either).
I would love to hear your opinion on this matter.
Best regards,