Catholics/My book review of How God Became Jesus may be of interest
Some of the texts of Mark begin with "This is the beginning of the gospel of Jesus Christ." (In the Greek text Christ means the anointed one.) Others begin with "This is the beginning of the gospel of Jesus Christ the son of God." Because of its added length and grandeur this is most likely to be a copyist's later addition. Mark 16:9-20,the longer ending, has been called a later addition from the 2nd century to the Gospel of Mark by most New Testament scholars in the past century. The longer addition appears in English Bibles; its origin is uncertain; a medieval source ascribes it to an elder Ariston (Aristion), perhaps the man whom Papias (c. A.D. 135) calls a disciple of the Lord. The evidence for Jesus' claims to be divine only comes from the last gospel, John, not the earlier ones. Biblical and historical scholars decided long ago that the gospels of the New Testament were not written by Jesus' disciples. The gospels are not critical history they are theology. The earliest book of the New Testament is Thessolonians 1, a letter written by Paul. He warns about the imminent End Time also supposedly foretold by Jesus. Also see the book: Voting About God in Early Church Councils by Ramsay MacMullen. Christian bishops, by popular vote, officially proclaimed Jesus to be God at a Church council, A.D. 325. The First Council of Nicaea was a council of Christian bishops convened in Nicaea in Bithynia (present-day Ýznik in Turkey) This put an end to the then theological argument that Jesus was of a lower rank and a submissive subordinate to God. See material on Arianism. In the earliest art Jesus is sometimes bare headed like Apollo, and bears a wand. Some of the earliest Christians may have thought Jesus to be a sorcerer, magician, or divine man with magic power. In catacomb frescoes of the third and fourth centuries Christ is frequently represented performing miracles by means of a wand. Peter is the only Apostle, in early Christian monuments, who is shown with a staff or wand, apparently as a symbol of his superior position. Ehrman believes Jesus may have thought of himself as the Messiah, Son of Man. Ehrman speculates Judas' betrayal was that of Jesus claiming that he was to be a king. I am a long time member of the Association of Ancient Historians, but I am not a professional historian only a curious amateur.
Charles, the short answer is that the Son of God existed from eternity and became man Jesus Christ in Judea some 2000 years ago.
Jesus did not write books but spoke in the manner of the oral society at the time. Many of his hearers and hearer of those hearers wrote down Jesus' message during many decades after Jesus' resurrection.
Some of those writings [not all, nor just those by persons whose names appeared on manuscripts]became accepted as inspired writings. These accepted and inspired books were agreed upon about three centuries after the resurrection. So, that someone did or did not add some verses to the original manuscript is irrelevant to their being accepted.
The consensus of the authoritative scholars at that time debated and stated in their language what today we call the Trinity. Arianism languished in many factions but was never accepted.
While there are many speculations about what might have been during the lifetime of Jesus, we do know sufficient for the important aspects of His life and teachings.
God does not speak or communicate untruths but the way, that is, the truth and the lifegiving light. Truth is not error. If God wants to convey truth, He owes it to Himself to see that the message is not corrupted into error.
Also, art forms are attempts to depict the mystery of God. Not only the early Christians but also their Roman persecutors knew that Jesus was not exactly what artists dreamed. Among the earliest and cryptic symbols for Jesus was a fish, whose Greek spelling contained the first letters of the creed: Jesus Christ, God's Son Savior.
As always, I hope my thoughts are of some help in your journey.
May God bless your efforts.