Are you familiar with the Third Ecumenical Council? Would you have identified with Nestorius? Do you agree or disagree with his beliefs?
Mary is called the Theotokos. This is properly translated as God-bearer. Mother of God is a poor translation choice.
Mary is the God-bearer because Jesus is one person and not divided. The title Theotokos is important because of what is says about Jesus, and not what it says about Mary.
Mother of God is a poor translation because it starts with the mother, while God-bearer is the proper translation because it starts with God.
The council of Chalcedon includes the following the Virgin Mary, the Theotokos, as regards his manhood.
So Mary is the God-bearer because she bore the manhood of Jesus. The Mother of God nonsense is tiresome. It is used an an honorific to increase the prestige of Mary, when the origin title Theotokos was to acknowledge the true nature of Jesus.
It's not about Mary, it's about Jesus.
Nestorius emphasizes the disunion between the human and divine natures of Jesus. There is no “disunion” and it’s connotation. However, Jesus was fully man and fully God. We cannot understand that nor should we attempt to. Jesus at time spoke as a mere man at other times He spoke as God/man. There is no way for the mind of man to understand how that works. If Jesus spoke at times as a mere man we can accept that He understood the difference. For Catholics to go beyond the words the Holy Spirit used when calling Mary the “mother of Jesus” is to inject inferred meaning and is going beyond what the Holy Spirit had written.