Jesus wasn't a mystic in the dessert.
And it's in some ways easier to know what was written 2k years ago because of how much time and effort people put into getting those things correct.
Look at the cuneiform tablets that get uncovered. A whack load of them are just tax transactions. No one questions their authenticity because of their antiquity.
Hardly anyone questions if Plato or Aristotle and the like exist, even though some of their missives only survive in parts of a single document, not the literal thousands of exact (or near exact) copies of various parts of the canonical Bible.
It's more than a bit silly to critique the historicity of the documents that comprise the Bible.
