Problem with this approach is that we do not find a mundane man in the Christian texts.Me? I'm only considering possibilities that seem like realistic possibilities to me.
No, I also don't have evidence that he wasn't from the planet Krypton, but I don't think I need any to rule that out.
Whereas a normal bog-average human man with no supernatural superpowers and with a few followers willing to make up tall tales seems like a very mundane and plausible possibility.
What we have is literally a superman, he just doesn't have a cape and we know the claimed historical facts in the biblical texts are (to be generous) erroneous.
What you are doing is saying "the biblical Jesus is a superman, the historical evidence in the bible is bunk but it all could have been based on a real person".
Now of course it could have been based on a real person, and we do indeed know myths do arise about people we can conclude by other evidence did actually exist.
However what we also know is that for many of the more recent religions we have documentary proof (from eye witnesses at the time, from documents, from arrest warrants and so on) that they are made up from whole cloth or a reweaving of existing beliefs, the Superman in DC comics is an example of how a mythical superman can be created.
We also know these religions are often made up by a singular person who is charismatic, strong willed and arrogant, who will reinterpret current beliefs and rely on claimed revelations to support his or her claims and thus proof of his or her new religious message.
And what do we find in the biblical texts?
A charismatic, strong willed, arrogant man who reinterpreted some existing beliefs and who relied on claimed revelations to prove his new religious message was The Truth.
Problem is that person is Paul.
So whilst there could have been a real historic Jesus we certainly do not need one to explain the origins of christianity as we know it today.
And we certainly don't have evidence for a historical Jesus that we can tie into what we know of the origins of christianity. Until we do I'm of the view that Paul "invented " what we know as Christianty and Jesus as the Christian's hold him to be was an invention of Paul.