These are the sorts of questions that a good grasp of history will really add color to. Jesus was a Jew, he was borne into the Jewish faith, of Jewish parents, and retained his faith until the day he died.
The Romans, over a hundred years after Jesus died, took the Jesus myth, which had by then become quite popular amongst a certain subset of Jews, who then called themselves Christian, and codified a new religion around it.
This question assumes that there is some level of success Jesus could have had that he didn’t actually have. There is no such thing. Jesus was fantastically successful. He was embraced by the population and he did teach all that he knew.
It’s just that creating a new religion was, and still isn’t, a simple or easy thing. Jesus didn’t have the infrastructure. The only thing Jesus could have done at the time was to add to the existing Jewish religion.
To posit an existence where Jesus could have done better is not to imagine a different social world, but to posit a completely different level of technology and social organization. Only in modern times can a normal person seriously affect the zeitgeist.
We’re not in the realm of alternative history anymore, we’re in the realm of science fiction.