Many apologists spend quite a lot of time trying to prove that Jesus really existed, that he wasn't just invented by the New Testament authors, that he wasn't just a fictional character or a myth. They do this as if proving Jesus' existence somehow demonstrated his divinity and the truth of what he said.
This is a very odd type of argumentation. Just put the same kind of argument in a different context to see how ridiculous it is. For example, imagine a Mormon trying to argue that Joseph Smith really was a true prophet of God, by proving that Joseph Smith really existed. I don't think anybody would be convinced that he was any kind of prophet of God by simply him existing.
Yet many apologists make a big deal about trying to prove that Jesus did really, truly exist.
The thing is, most of this is pretty useless. A skeptic doesn't need to argue against the existence of such a person. Ok, let's say that there existed a person named Jesus, and the New Testament are based on him. So what? We can perfectly well grant that argument. It still proves absolutely nothing.
This is nothing strange. There are plenty or examples of myths based on real people. For example captain Blackbeard was a real historical person, but he is surrounded by a lot of mythology that's probably not true. The list of such persons would be quite extensive. Why would Jesus, if he really existed, by any different? Existence in itself demonstrates little, so there's little point in spending so much effort in trying to prove that.