You should do some reading.
Why wouldn't you think, as someone who clearly doesn't believe he had all these "powers", that it's likely a regular dude had existed if one of the biggest religions ever is based on this dude?
How do you think Jesus was invented then?
I mean, that's not a very good line of thinking. We have a lot of examples throughout history, and even in modern times of widely believed things that were completely made up. Checkout snopes.
Studying the archeology in context with the writings we have and making sure we get at the earliest recollecitons of Jesus is where clues to his historicity start to arise.
First, the earliest wirtings don't even mention him having supernatural powers, certinaly one mention him being god/the holy spirit, etc, or even of having risen physically from the dead. These are later additions.
Some clues lie in, funnilly enough, in stories we KNOW are false. For example the various nativity narratives. From the slaying of the children to the census that required going bakc to some ancestral home. The former is very unlikely to have happenned, while the latter, definitely did not happen. But then why go to the trouble?
Well, there were a lot of Messiah myths and prophecies at the time, many featuring a Messiah that was born in Bethlehem. So you want your guy being born there... but again, why go through all the trouble of making up stories to get Jesus of Nazareth to have been born in Bethlemhem?
One possible reason is that people knew Jesus of Nazareth. And so you had to say: "Nah, the guy was actually born in Bethlehem! You won't believe this story but...".
If he was entirely mythical I don't think they would need to have bothered.