Moses and exodus are completely counterfactual and at once central to Jewish and Christian mythology and identity. Our foundational stories are mostly lies because reality is depressing.

Egypt exists even though the Exodus never happened. The mere existence of factual elements doesn't mean a foundational myth is real. Myths are normally interwoven with real elements.

Moses is almost entirely distinguished as a personage by elements we know are nonsense. If you found a Jewish leader named Moses who lived in a different year who experienced an entirely different history you wouldn't have found the real Moses so much insofar as the symbol Moses is a reference to the myth not the hypothetical actuality. Likewise finding an early leader wouldn't mean Remus was real