This is from this article.
He rightly said "the sky is the limit now", while Joshua will look back on a US bow which was wrecked.
That is an odd use of "bow".
You can use "bow" to mean "final appearance", as an actor's final appearance on stage is to bow to the audience. But that doesn't fit the context here, as Joshua was not intending and does not intend this to be his final performance.
So the other possibility is that it is a typo for "bout", but that seems to be a surprisingly bad typo for a well-edited site like the BBC. And the meaning there doesn't quite work, as the bout wasn't wrecked (it just didn't end the way Joshua hoped or expected)
It could be an attempt at extending the metaphor of the "sky's the limit" to "the bow of the sky", but that isn't obvious.