yes, there probably was some guy that Jesus was based on. I'm a history buff, and I like roman history. around that time there were a bucketload of nuts claiming to be the messiah. People who believe themselves oppressed always have leaders appearing and disappearing.
I think that all historical fairy tale people such as robin hood, Jesus, Mohammed, Arthur, all have some basis in a real person, BUT, and this is the big one, some dude saying, treat other people nicely, etc etc, is not that novel in the history of our species. Nor is that a basis for claiming divinity.
the only truth In the accounts of supernatural activity is the desperate need of our species to find meaning in an otherwise meaningless life, and the incredible evil of those who debilberatly exploit others grief and pain.
The one strength science does have is that it constantly tests itself and says , we just don't know... but it provides a much better option than attempting to use a fairy tale figure to explain the otherwise unexplainable.