I'm not sure what you mean by Orthodox. I'm guessing it means what ever you want it to. Neither of the words "Trinity" nor "Triunity" appear in the Old Testament or New Testament. The first recorded use of the word "Trinity" in Christian theology was in about AD 180 by Theophilus of Antioch who used it, however, not to describe God, but rather to refer to a "triad" of three days: the first three days of Creation, which he then compared to "God, his Word, and his Wisdom." It was Tertullian, a Latin theologian who wrote in the early third century, who is credited with using the words "Trinity" and "person" to explain that the Father, Son and Holy Spirit were "one in essence— not one in Person." About a century later, in AD 325, the Council of Nicea established the doctrine of the Trinity as orthodoxy and adopted the Nicene Creed that described Christ as "God of God, Light of Light, very God of very God, begotten, not made, being of one substance (homoousios) with the Father." Further, Jesus and his followers didn't contradict the Jewish Shema Yisrael: "Hear, O Israel: The Lord our God is one Lord" (Deuteronomy 6:4).Encyclopedia of Religion, for example, argues that "God the Father is source of all that is (Pantokrator) and also the father of Jesus Christ. Early liturgical and creedal formulas speak of God as "Father of our Lord Jesus Christ"; praise is to be rendered to God through Christ (see opening greeting in Paul and deutero-Paul). There are other binitarian texts (e.g., Romans 4:24; Romans 8:11; 2 Corinthians 4:14; Colossians 2:12; 1 Timothy 2:5–6; 1 Timothy 6:13; 2 Timothy 4:1), and a few triadic texts (the strongest are 2 Corinthians 13:14 and Matthew 28:19)."
Mainline Christian denominations believe that the Father, Son and Holy Spirit are the only Deity.
Don't know if you believe this. But Mormons do not.
You do well at mining and compiling information for argument.
But I’d like to know what you actually believe for perspective if you don’t mind.
I’m Southern Baptist and don’t attend regularly but do beieve and on occasion attend Charismatic services.