Polyamory vs polygamy vs biblical polygamy
There is a difference between the terms that can help us understand.
Polyamory is multiple loves. It doesn't really have a set guideline of configuration. It can have can be a person with many individual loves, a couple who date together or separately, or any M or F or T(trans) configurations.
Polygamy is a relationship with multiple(3 or more) people that wish to be married to each other.
Biblical polygamy is a man and multiple women. It states that a man should have their own wife and husband have their own husband. But in the old testament the meaning for the two "their" is different. for the man to the woman is means master over, like his property. he can have as many wives or property as he liked. for a woman it reflects ownership, as in she has one owner. Jesus is the master and as churches we are his children. many children/churches are included but only the one master is allowed.
Hopefully that clears up what I understand the differences to mean.