Tammuz was the name Istar gave her son, and falsely claimed he was the virgin born reincarnation of her husband NMRD.
Mother of God has been her title for over 4000 years; I wasn’t there, but I believe what God’s word says, and it was borne up by the historical literature long before there was a Mary. That is where Constantine got it; he was a devout pagan himself.
Your logic would support saying the virgin birth of Our Lord has the same source of myth.
1. The title Theotokos is older than Constantine; the synod discussed it when it was first rejected, not when it was first promoted. So Constantine’s former paganism is irrelevant. Church fathers who used Theotokos before Constantine (325) include Origen (250), Gregory (268), Dionysius (275), Peter of Alexandria (304), Methodius (305) and, if Augustine is to believed, the apostles themselves.
2. The wording of “Theotokos,” admittedly lost in translation to English, does not suggest the passing on of a divine nature; That Jesus got solely from his Father, as Catholics understand quite well. Theotokos means, “one who bore (in childbirth) God,” and that is the understanding held by Catholics.
3. Nimrod was a mortal king. He is of no relation to Tammuz, other than he plausibly worshipped Tammuz.
4. Tammuz was not the son of Istar, nor was he born of virgin birth. In fact, Ishtar was the goddess of prostitution, and was very promiscuous, “the courtesan of the gods.”
5. Istar was never called the “mother of the God.” In fact, to my surprise, she is not called the mother of any significant god, even though it’s common for pagan gods to be called mothers or fathers of other pagan gods.