Is there a canon story or ending to Bandersnatch?

No, the whole point is you can pick your ending based on your choices. And every ending is equally valid and there are 5 major endings.

From Hollywood Reporter

Officially, Netflix says there are five “main” endings. But there is a caveat: There are variants on all of them.

“It’s a little bit crude to think of it in terms of specific endings, because they could all co-exist,” says Jones. “We tried to create it so that all of the endings make sense for Stefan. He would like a few of those experiences to come true. And then we want people to experience it and have their own emotional reactions.” - Source

And form another article of Hollywood Reporter

“We don’t really want people to exit and start playing again,” says Jones of how to play, since the state tracking lets the character learn as he goes through the different branches. “Every time you get to an end, you can exit and restart from the beginning, or you can keep going and then we’ll give you shortcuts to bits that we know you haven’t done yet,” Brooker adds. “Eventually, there is a point that you will arrive at just credits. But that means you’ve seen almost everything.” (One ending is also intercut with credits because Netflix determined that it would be the most common ending reached.)

Despite all the options, there are no right or wrong choices. And there is no right or wrong ending. “There’s no correct path,” Brooker assures, though he adds that it’s “entirely possible” to not arrive at all of them. “It should be more so felt as an experience,” Jones explains. “Depending on which route you take, you may feel like you have come to a natural point where you feel sated. There are a number of distinct what we call ‘endings’ but you may not feel that is an ending. They all build and payoff. There are many ways that you can watch the film, but it should all build to one interactive experience.”