Thanks to Dragon Ball creator Akira Toriyama, there’s official confirmation of when Dragon Ball Super: Super Hero takes place in the series’ timeline, and that it's actually canon. While Dragon Ball Super is supposed to take place before the original ending of Dragon Ball, there’s always been some ambiguity about when exactly the stories are set. While the first arc takes place four years after the Buu saga, other stories didn’t have their timelines explicitly stated.
https://screenrant.com/dragon-ball-creator-superhero-timeline-placement-confirmed/