(sorry, I cut my response and I must edit your text due to limits)
The monogamous, traditional family unit is a proof of the Trinity. As one saint remarked, in any relationship, “
there is a lover, a loved person and a fountain of love”. In short, a relationship is perfect communion. That is what the Trinity is - perfect communion between God the Father, God the Son and God the Holy Spirit. This explains why the monogamous traditional family unit is sometimes referred to as the “Church in miniature”, and even since Old Testament times, foreshadowed the Church’s existence that was to emerge in the New Testament. In the Garden of Eden, Adam and Eve were made in “
God’s image” (cf. Genesis 1:26). This not only meant that Adam and Eve had a soul, but also that their relationship was indicative of God’s existence, to which they are instructed to “
be fruitful and increase in number” (Genesis 1:28).
It doesn’t work this way with a polygamous family unit… multiple wives, or multiple husbands, ultimately leads to loving multiple gods… Abraham was originally a pagan… King Solomon’s downfall began when he started marrying multiple wives… Max Weber, who is regarded by many as the founder of the field of sociology, referred to polygamy as an essential feature of barbaric civilizations. It is not something you find in more advanced societies. It is certainly a statement interesting in light of China’s economic growth and their huge male-female ratio gap…
Back to the point, God gave Abraham and Moses huge tasks because they were sinners. Yes, sinners. It is an implicit
Catholic myth that God only gives huge tasks to those who are perfect. That is not true and is clearly anti-biblical. In fact, those who are perfect tend to be overlooked, indeed - " “
It is not the healthy who need a doctor, but the sick” (Luke 5:31) and
"there will be more rejoicing in heaven over one sinner who repents than over ninety-nine righteous persons who do not need to repent" (Luke 15:7). The reason God gives sinners such huge tasks is because when they accomplish said task, they give glory to God. If a perfect person was to accomplish the task, he/she would attribute it to his/her own talents. This explains why God gave Gideon the duty of fighting the Midianites, even though he was the youngest and least important in his family. This explains why God gave David the duty to fight Goliath, even though Goliath outsized him by an unimaginable factor. This explains why God’s own beloved son, Jesus, was born in a manger, and not even his own people recognized him: “
Though seeing, they do not see; though hearing, they do not hear or understand” (cf. Isaiah 42:20; Matthew 13:13). Peter wavered in his faith all the time, yet he was the first Pope and was given the keys of Heaven.
It’s easy to get sidetracked into the sins Abraham and Moses committed because Catholic spirituality of the saints indirectly asserts “you need to be perfect to be noticed by God”, but this couldn’t be further from the truth. Those who were perfect in the Bible were overlooked. None of them were important, and none of them are remembered for any contribution they made in biblical history. At times like this, you should resort to the Bible and not teachings of men

: “
But the LORD said to Samuel, "Do not consider his appearance or his height, for I have rejected him. The LORD does not look at the things man looks at. Man looks at the outward appearance, but the LORD looks at the heart” (1 Samuel 16:7).