Not for purposes of this discussion, which is concerned only with the existence (or not) of Nazareth.
As for John's Gospel itself -- well, I have to admit it's my least favorite. It reminds me too much of Thucydides, who created speeches for people based on what they "would have said."
Jesus's speeches just don't read like they would have been spoken. I don't think John actually made anything up -- I think he worked awfully hard to write down Jesus' sayings as he remembered them from a long time earlier, and his personal writing style (and nascent theology, in all probability) got in the way.
He probably never heard JC speak. Few did. The words are largely formulaic, as are the events. All the same, that is my fav Gospel, together with the writings of Paul, especially the genuine ones. That was the seedling of early Christianity in the great time before the Corporation took over.