OK--let us take the stance that the NT is composed of a bunch of bull.
Now the question I have is--why waste time creating it? What goal was in the minds of these various people to make their versions of a book that they have to have known had nothing to do with reality?
I guess another question I have to ask is-"What events would lead to the desire of a new religious concept in Israel?" Apparently, it wasn't the Jewish religious order because many of the concepts in the NT damns them and relatively dismisses Judaism.
I guess the creators of the NT did not fully appreciate the history of the Jews and there experiences of exile and exodus. If they did, the NT would have been written radically different than it is now.
Okay, a couple of thoughts.
When you talk about the books of the New Testament, you are talking about 26 or so books that were accepted as "Canon" out of hundreds of gospels, Epistles, Acts and Apocalypses that existed at the time, written by dozens of factions of people who called themselves "Christians".
So putting them in the historical context might be a better thought.
The Epistles, written 50-80 AD came first. Some were written by Saul of Tarses (AKA St. Paul) others attributed to him. Saul had more to do with spreading Christianity than anyone else. But two points. Paul never met Jesus, and his epistles are largely lacking biographical details.
Next you get the Gospel of Mark. Mark has some biographical details, but is intentionally vague. It is also clear Mark never visited the Holy Land. He gets geography and customs wrong.
Then you get the next two gospels, Luke and Matthew. 90% of Mark is copied into these two Gospels and a second document called the "Q-Gospel", but they both enhance the story with biographical details. And since neither of them knew Jesus either, they contradict each other.
Matthew was written for a Jewish audience, and puts in a lot of misattributed scripture quoting to create Jesus bona fides. Luke is written for a Greek audiences. He puts in a lot of historical detail that contradicts the others and makes things questionable. (His literary device to put Jesus of Nazareth in Bethlehem is very amusing.)
Then you have John, which is written at a time where where the split between the Jews and Christians is pretty severe. So there you get all the blaming of the Jews for Jesus death that Mel Gibson is so fond of.
All four contradict each other on when Jesus lived, who his followers were, and so on.
And keep in mind, these were the four gospels picked out of hundreds by the Romans 300 years later to try to standardized their church.