In general, the Dragon Ball Super manga is accepted as canon. It aligns with the established lore and storylines of the Dragon Ball universe and is recognized by the creators and fans alike.
The Dragon Ball manga is typically seen as canon. It serves as the foundation upon which the entire franchise is built. There may be some spin-offs or adaptations that deviate, but the manga itself holds the primary status of canonicity.
Overall, the Super Dragon Ball Heroes manga and anime share a similar core story, but the anime often adds more visual effects and action scenes. Some storylines might progress at different paces in each medium.
The story length of Super Dragon Ball Heroes World Mission varies depending on how quickly you progress and explore all the content. But generally, it can offer several hours of gameplay and story.
It probably wouldn't fit directly into the main canon as it's a rather light - hearted and comical concept. But it could exist as a side - story or an 'alternate universe' type of fanfic. It can show the characters in a more relaxed and fun - loving situation that we don't often see in the main series.