Mary is the originator of His human body and not His God nature.
This is true. Jesus did not derive His divinity from His mother. But this did not make her any less His mother.
If I may refer you to Luke 2:41-52, when the 12 year old Jesus went to Jerusalem with His parents, Jesus tarried as His parents returned, and when they found Him not, they turned back to Jerusalem seeking Him. I’m sure you know this story. When they found Him in the temple, “they were amazed: and his mother said unto him, Son, why hast thou thus dealt with us? behold, thy father and I have sought thee sorrowing.” And he said unto them, “How is it that ye sought me? wist ye not that I must be about my Father’s business?”
Was this not Jesus speaking in His divinity? Yet this divine Jesus “went down with them, and came to Nazareth, and was subject unto them: but his mother kept all these sayings in her heart.”
What part of “don’t put words into the Holy Spirit’s mouth” do you not understand. Or do you not think the Holy Spirit knew what He was doing by not calling her the “mother of God”?