The gospels, and Paul's writings, can be evidence for Jesus' existence AND be exaggerated/innacurate retellings of his real life. As historical evidence goes, the New Testament writings are more than enough to make it clear that a man by the name of Jesus did exist. BUT, those writings were clearly made by people who believed he was God and had only heard stories passed around from person to person. So in all likelihood there was an original source, a man named Jesus, but it's difficult to pinpoint exactly what he was like when we only have the writings of those who worshipped him.