The Trinity is based on the fact that there are 3 that bear record in Heaven, The Father, The Word/Christ, and The Holy Spirit.
That fact can only be denied by someone who refuses to accept reality. As I said, the word "Trinity" is not found in Scripture, it's a reference of identification to The Father, The Son/Christ, and The Holy Spirit, what is referred to as the Triune Godhead/Trinity.
I've studied the history and will ask the question, whose account of history is that? I get my information from Scripture, not the accounts of uninspired history outside the pages of Scripture.
Anytime you read the word "begotten" in Scripture it is referring to the incarnation of Christ, Him becoming man.
As far as the "duel nature" of Christ, the only person who could describe that is the one Christ chose to give His revelation, that revelation is the meaning of the New Covenant, and that chosen person was Paul of Tarsus, the apostle Paul.
Peter, James, John, and all the rest of the apostles did not have this knowledge. They had a partial knowledge being that God had chosen to grant salvation to the Gentile world. All the Jews at this point believed salvation was only for the Jew.
The truth is that the Apostles learned from Paul the meaning of the New Covenant just as we do, but they also had the great privilege of hearing some of it directly from his mouth. Peter tells us that some of the things Paul said were hard to be understood, and some wrestle with it to their own destruction. Peter didn't understand all of it because it wasn't given to him to understand, but he knew Paul had been given this knowledge and accepted that fact.
Do you have a verse to go along with any of this?