In the manga, Gohan never managed to defeat Goku. Their battles often ended with Goku coming out on top or the fight being interrupted for some reason.
In my opinion, it's highly unlikely. Goku has mastered multiple forms and techniques that give him a wide range of powers. Saitama's one-punch style might not be effective against Goku's diverse skills and battle experience.
I don't think there's a clear winner. Both Manga Goku and Manga Saitama have unique and powerful abilities. It could come down to strategy, luck, or even the author's imagination!
Goku's victory over Hit in the manga was the result of his perseverance and the ability to surprise Hit with unexpected moves. Also, his experience in battles played a significant role.
Bulma could be one of the main characters. She has been with Goku since the beginning and could play a role in bringing the reader and Goku together. Maybe she discovers some old technology that has a connection to the reader and uses it to reunite them.