The universe existing as a byproduct of God?

[FatAndFaithless]

They are evidence that they believed certain things, yes.  They aren't evidence that they're beliefs are actually true.

So then the NT is a description of what contemporary people believed to be true with respects to Jesus' life and claims. Why would they believe it to be true if in fact it was not? Many would be eyewitnesses or had access to eyewitnesses.

That statement could be literally applied to any description of any holy figure of any religion.