This isn't about "monothesism". It's about the Abrahamic religions of Judaism, Christianity, and Islam, with a strong focus on Christianity. They are related branches from the same root religion, and have their source in the same part of the world, with a relatively recent basis, evolutionary speaking.

A serious analysis would ponder the transition from the Ancient Canaanite religion through Abraham's rejection of idol worship, and the strictly monotheistic Judaism developed during the Babylonian captivity.

A serious analysis would look at other monotheistic religions, like Zoroastrianism and Sikhism.

A serious analysis would consider why so much of the world was polytheistic, before the spread of the Abrahamic religions.

A serious analysis would compare us not to the silverback gorilla but to our closest living kin, the bonobos and the chimpanzees. So close, and yet with very different social and sexual behaviors both from us and each other.

I'm not even sure how to understand the part about infanticide. The quote from Num. 31:17-18 looks like a call for ethnic cleansing, leaving only the virgin girls. It's not, strictly speaking, infanticide. Regarding infanticide in general, and quoting Laila Williamson from https://en.wikipedia.org/wiki/Infanticide "Infanticide has been practiced on every continent and by people on every level of cultural complexity, from hunter gatherers to high civilizations, including our own ancestors. Rather than being an exception, then, it has been the rule." That Wikipedia page then says "Judaism prohibits infanticide", "Christianity rejects infanticide", and "Islam Infanticide is explicitly prohibited by the Qur'an".

This is not a serious study. This comes across as one of those just-so stories that evolutionary psychologists seem to love to put together.