For us muslims its plain simple Jesus pbuh was prophet and messenger of Allah, we reject all the socalled divinity claimed against Jesus.
But when it comes to christians, they are so divided about him!
1) trinity
2) son of god
3) two nature
4) incarnation of god
5) angel michael
6) prophet and messiah( Early jewish christians)
Any religion that grows to a certain size is going to become factionalized. You question has already been answered, basically, however, there might be other answers. The Xian faith grew outside of a Canon, a text. When the Scripture was written down, as is the case with all language, the narrative can be interpreted in various ways.
Backtrack.
The pagan priesthood temples in Europe, wanted to maintain power. They had to stay legit, while, at the same time, advocating this ''new' religion. Major problem. So they incorporated, and meshed, some beliefs, into Christianity, the new religion which was essentially taking over, with their own beliefs.
We are, to an extent, unable to ''prove'' certain things about our beliefs; yes, there is disagreement. I find myself, unable to ''prove'' certain beliefs I have about Jesus, etc., from Scripture. There is interpretational room, here. There is a way to come to a few different conclusions, from reading the same text.
This is where, the earliest traditional beliefs, would come into play.
My beliefs, that Jesus is literally G-d, and the 'trinity' is like a description, rather than three separate individuals, is what I believe the earliest beliefs to be. Yes, many disagree. However you really need to study this material, outside of a church bias, etc., to start to understand how the various interpretations came about.