There were as many Jesus stories as there were people telling the stories.
Mystics from mystery schools, Gnostics, Messianic Jews, apocalypticists, pagans, cynics, you name it!
Each of these versions competed for the interest of anybody who would listen.
Over time the stories had grown into a genre.
At some point they were written down. Claims were made. Arguments ensued.
The names of important apostles were attached.
Then, at a given place on a given date some person or persons sat down and sifted through what was available. They picked what appealed to them and got rid of all the competition.
The AUTHORITY of the state, of the empire gave a stamp of "authentic" and the rest is history.
Voila! Canon!
Over the centuries these competing versions have popped up here and there.
Some of them sound very strange to our ears today. Others, more feasible.
What it comes down to is that EACH PERSON CHERRY PICKED the story they could go along with. They repeated THAT story version.
There really is no way to know what, if any, was authentic.
Why?
THERE IS NO PROVENANCE. There are only claims.
What standard of proof you possess is YOUR filter.