Young Jewish man runs into a Buddhist or at least Buddhist ideas in his twenties, spends a while learning about them, comes back to the temple in his thirties and starts telling people how great it would be if they were just nice to each other and maybe focus less on rules and hypocrisy. Gets killed by a Roman state that’s worried about uprisings and local Jewish leaders who don’t like different ideas. His followers tell stories about him in the following decades focusing on it being better to be poor, repressed, the Roman state feels threatened by a powerful underclass religion so they coopt it, make it the state religion, and shape it to be useful to empire. Ultimately it kind of contributes to the already crumbling empire.

All conjecture but reasonable enough.

If you start with the premise that Jesus was a real person but not divine, I think the real story would look a lot like that.

Agree, reasonable this might be closer to the real story. 1)Answers: what happened to the 12 years; 2) Why the stories were written decades later; 3) the co-opt seems likely at the 325 Council of Nicea.

As far as 2) scribes were expensive then, and paper/skins even more so. The stories weren’t written down until it was clear they were ‘hot’ and worth it.

Same with Buddhism, near as anyone can tell. None of the scripture is contemporary with Buddha.

I can even imagine one story being about "my teacher once met this dude who said we should be nice to each-other" and "a cousin heard about this guy who said that poor people should be helped by neighbors" and those somehow merged and became one person one story.

It happens today, in an era where information is/appears much more precise, people and attribution is common. e.g. quotes being attributed to Einstein or some rock-star, or actors "cancelled" for stuff some other person did or said.

I kinda always wonder about Romans doing the killing. Was it because there was something going on. Or was it the easy route out asked by local dignitaries. Hey please get rid of this guy for us. And they just obliged to do the deed. Whole washing hands of the thing points me to that direction.

Likely both. Rome had some control over the religious leadership as well. So this somewhat at least revolutionary annoyed ordinary Jews, the local Roman influenced religious leadership, and the local Roman authorities by being perceived as a kind of revolutionary at minimum in a religious sense but also in a actual sense regardless of the truth of these things.

The annoyed religious leadership referred him to the local Roman in charge of such things who had him executed.