Not a real historian, but I have a religious studies degree and this post seems lonely. Up until the Babylonian Captivity where many people from the Kingdom of Judah were held captive (5th-6th Century BCE), the early faith that laid the foundation for modern Judaism was monolatristic rather than monotheistic. This means the ancient Israelites did acknowledge the existence of other gods, they just pledged to only serve and worship YHWH. And yeah, they definitely saw theirs as the best and most powerful. In those days in the Near East, wars against different groups of people were really seen as wars between opposing gods, and whoever’s god was more powerful would win. So I think the phrasing of the First Commandment is reflective of this historical context. No other gods “before me” can allow for the acknowledgement that other gods exist while requiring YHWH to be #1 mac-daddy. But then Jerusalem fell to Babylon and many Judahites were exiled, aka the Babylonian Captivity. This turn of events was seen as a punishment by YHWH for disobedience and unfaithfulness (idolatry, etc). Once the Babylonians eventually fell and the exiles could return to Judah, the second temple was built and sort of signifies the rise of Second Temple Judaism where many laws and cultural norms were clarified or established. One of those being a shift from monolatrism to a strict monotheism revering YHWH as the one and only god existing. So there definitely was a journey toward monotheism rather than it always being a pillar of the Israelite faith. And that journey is heavily influenced by the historical events and cultural shifts the Israelites experienced.