5:116 On the Resurrection Day, God will say: O Jesus, son of Mary! Did you say to mankind, “Worship me and my mother as gods besides God?" He will respond, "Be You Glorified! I could never say that was not my right. If I said such a thing, You would certainly know it. You know what is in my mind, and I do not know what is in Your mind. You are the Knower of what is beyond human perception.”
Brother Tayo, the verse does not mention the word trinity so it is not saying The Trinity is God, Jesus and Mary, but stating a fact that some christians have taken Mary as an 'object' of worship. Roman Catholics to this day still pray to Mary as:
"Hail, holy Queen, mother of mercy, our life, our sweetness and our hope. To thee do we cry, poor banished children of Eve. To thee do we send up our sighs, mourning and weeping in this valley of tears. Turn then, most gracious advocate, thine eyes of mercy toward us, and after this our exile, show unto us the blessed fruit of thy womb, Jesus. O clement, O loving, O sweet Virgin Mary! Pray for us, O holy Mother of God, that we may be made worthy of the promises of Christ. Amen."
The christian god has had many manifestations from one God, Jesus being a messenger, to God and Jesus being both gods, to the adoption of the holy ghost in the god trinity in the fourth century, and, as you have detailed, the deification of Mary. The Quran is not there to detail every stupidity but highlights the gross absurdities and expects them to think about everything else. Most muslims are in the same boat with other nonsense beliefs and acts!
Some muslims run away from this verse because they have not read it with understanding and have accepted the christian charge that the Quran does not know what the trinity consisted of! You have shown these christians do not know what some christians have believed and the Quran remains a truthful text.