Here are some good reasons to think the theory that the Romans invented Jesus, a theory peddled by the amateur scholar Joseph Atwill, is not a very good one:
It relies on dubious hidden “codes” in the Gospels and the works of Josephus that for some reason no one has been able to see until now. This makes it more likely that the messages are in Atwill’s imagination, and not the text itself.
We know how the books of the New Testament were selected and it involved bishops working within the Church, not Roman aristocrats.
Atwill claims the Romans invented Jesus to pacify rebellious Jews in Judea. If that’s true, then why did they write the New Testament in Greek (as opposed to Hebrew) and why did they create a story and theology that Jewish people considered a “stumbling block” (as Paul says in 1 Corinthians 1:23) instead of crafting a more appealing savior figure?
Finally, if the Romans invented Jesus, why did they persecute the small number of Jews who ended up believing in the state sanctioned savior?
Hope this helps!