For some time, I have been saying that ‘monogamy-only’ is not a Biblical concept or teaching. In fact Greco-Roman law and pagan worship is the origination of such.
Here’s a quote from J A Farmer’s Does the Bible Condone Polygamy?

I’m looking forward to the rest of this book and how the author connects monogamy-only with idolatry. We must take this matter seriously! Willful ignorance will not be accepted by the King!