Canon is works made by the original author or their chosen successors.
Canon is a term for those who realize the original author or the person they chose to be their successor are the correct storyline, since, I dunno, anything else is fanfiction.
Fanon, if you will.
Filler obviously didn't happen since it was utterly ignored in Super, Hell operates on an entirely different rule book and Broly never existed.
It doesn't matter the format, the works of the original creator/author/successor are the canon storyline.
The works of numerous fanfiction writers or the paid fanfiction writers at Toei are meaningless to the actual storyline.
Granted, this won't affect anything; the Dragon Ball fanbase is so divided and cancerous (mostly) they can't be persuaded to change their view of anything, in spite of the reasoning.
They spout terms like "headcanon" to justify the divide when in reality it is "I don't care about the truth, this is my opinion"
Should say "Fanon" instead of "Headcanon", because that's all it is.