Actually we have much more than the paltry, edited material in the New Testament. But if that's what you choose to believe, so be it.
In fact, thousands of documents concerning Jesus, including his words, have been discovered in the last 75 years. (They dwarf the goverment-approved New Testament.) And they show that Jesus of Nazareth was a real person.
If you are interested, you might start with the life's work of Dr. Glenn Kimball. His decades of diligent research results are fascinating. He was a extraordinary scholar and a friend who contributed greatly to my writings.
So much for my taking the time to give you a detailed reply. Won't make that tedious mistake again!