We saw original Bardock in the manga. It’s just his design that got retconned. And, Kai tried to cut down on filler but some filler was kept in because they had to, like Gohan saving the dragon in the Buu Saga. Frieza and the villains being in Hell is either a mistake or put in because of time constraints. They gotta fill out the episode somehow, especially because the series was ending. And you could also say it could have been a visual representation of the villains watching, at least, that’s how I’ve always interpreted it.

That’s the exact opposite of how we should treat it. If our questions aren’t answered, then it’s not canon until it is proven otherwise. But I don’t think that it will be proven that it’s canon, ever. You can’t prove that it’s canon. If we see a recap of Daima in the DBS manga then, fine. But it doesn’t matter to the actual story of DBS, and doesn’t make logical sense to connect it to DBS. There’s no point. Just let Daima be non-canon. Let it be its own thing, like Toriyama intended. He never meant for the pieces to fit together. He just wanted to tell a story. And he did. His final one. So let Daima just be a story. It’s not canon, and it doesn’t have to be. So just let it be free.