“I guess, then, you do not consider the Father and the Holy Spirit to be God.”
You guess wrong.
“Since the Catholic argument is that Jesus is God and Mary is the mother of Jesus, therefore Mary is the mother of God, then the rest of the Trinity is either God or it’s not.”
False. Mary is only the mother of Jesus - who is God. She never gave birth to the Father nor the Holy Spirit.
“If it’s God, then Mary, being the mother of God, is by default, their mother too.”
Nope. Mary ONLY gave birth to Jesus - who is God. She never gave birth to anyone else, never the Father nor the Holy Spirit.
Since the Father and the Holy Spirit are non-corporeal beings there is no possible way for any human person to give birth to them. Jesus, of course, was not a non-corporeal being. He took on humanity - from His mother, Mary.
Mary is not in any way the progenitor of the GOD Christ. She can be thought of as the progenitor of the MAN Jesus, even as she was surrogate to His gestational period of human life.
You assert an unprovable item since you have no idea the DNA or chromosomal make up of the man Jesus. And if you are unfamiliar with such things, be advised the womb in which a child gestates adds NOTHING of chromosomal or DNA identity to the child; the gestating child builds ALL of the parts for its life in the air world, the mother if a surrogate adds NOT ONE Chromosome.
They are all one God...If Mary is the mother of one, she's the mother of all...