>> The pagan said all their gods had sex and thus childbirth. So, it would hardly be weird for Ishtar to be a mother of God. <<
This is interestinng...
On further review, Ishtar had her own husband, Tammuz, cast into the underworld. She was never a mother. (An older understanding of the myth presumed that she had gone to the underworld to rescue him.)
So, no, she is not even a “mother of God.” You’re just simply 100% incorrect.
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.