Myths can sprout up four minutes after an event, let alone four decades, especially in the ancient world, long before there was anything like mass media. Have you played the game Broken Telephone?

The wiki page on the question of the gospels' historical reliability gives an overview of what NT historians say:

https://en.wikipedia.org/wiki/Historical_reliability_of_the_Gospels

And I already asked you about the synoptic problem of the gospels. Are you familiar with that problem?

https://www.blueletterbible.org/faq/q.cfm