The point is, Kaido is not the one flying.
It's Onigashima.
Who is shooting the beam all the way from Onigashima is irrelevant. I don't give a fuck if it's Kaido, lol.
The picture that was being painted was that Kaido, as a dragon, was flying around destroying the Flower Capital after his loss to Luffy.
But it's not what we see in the opening.
So you should stop trying to force something that isn't the case.