First off, according to Judeo-Christian tradition, Monotheism WAS the original human belief, so the fact that some post-Noahide groups may have dabbled with it prior to the revelation to Moses doesn’t mean much of anything. This is especially true for Catholics, since we have a theological tradition of believing that Monotheism is actually rationally deducible, and doesn’t require special revelation. Furthermore, there are actually records within Scripture itself of apparently Monotheistic believers at the same time as Abraham: Melkizedek was the priest-king of Salem who gave sacrifices to God, for example, and Abraham went to Melkizidek to make his sacrificial offerings. Melkizedek seems to have no connection to Abraham, but was rather a native of the region Abraham traveled to, so Scripture records Monotheistic kingdoms prior even to Akenaten, but post-Noah.
Secondly, we already know that the Israelites weren’t solidly Monotheistic even after the Exodus; polytheism continued to be a problem for them until after the Babylonian Exile. This is attested to in Scripture itself, as it was the constant complaint of the Prophets. Abraham focused his worship on one God, and taught his descendents to do likewise, but there’s no indication in Scripture that they were anything but henotheists who tended to worship their one “tribal God”, who happened to be the greatest of the gods. Becoming pure Monotheists wasn’t completed until long, long after Moses.
The thing is, none of this even touches on the Judeo-Christian claims, since none of the Judeo-Christian argument rests on Monotheism being first held by the Jews, or that it required special revelation. On the contrary, the Judeo-Christian Scriptures absolutely attest that Monotheism was the original belief of humanity, and that we later fell to polytheism of various stripes, and even atheism.
The Judeo-Christian claim is simply that the “one God” revealed Himself uniquely to Moses and the Jewish people, culminating in the Incarnation and the New Covenant, and that is something that is utterly unaffected by Akenaten coming along before Moses. Moses wasn’t the first believer, nor was even Abraham, they were just specially chosen.
Peace and God bless!