People recover very quickly from being knocked out except a few exceptions.

Except for all those people whose status is completely unknown. You're assuming your conclusion.

Even people as weak as Jet and Abjullah or Dagma were up and going and they don't seem nearly as strong as someone worth 67 million.

Kelly and Bobby Funk were said to be able to take out people worth 100 million. Don't underestimate people just because of the high level of expectations in the New World; by the standards of anywhere else, even the weakest people worth mentioning are pretty much top tier.

Zoro received a bounty of 60 million for defeating Mr. 1 and the 100 bounty hunters at Whiskey Peak; Sanji got one of 77 million for his actions at Enies Lobby. Bellamy had a bounty of 55 million at Jaya. Gambia's 67 million isn't all that much by New World standards.

He seems to be the weakest VA we have seen.

We haven't seen anything from him. All we know is that he got beaten offscreen by Bartolomeo, and that this didn't raise a fuss (shortly after doing exactly the same to Gambia).

This assumption is based off the fact that many people in One Piece and specifically this arc have very fast recovery times.

They do... sometimes. Depending on who it is. We've certainly seen cases where Zoro or Luffy or Usopp or Chopper or Sanji or Franky was incapacitated for some time after a fight, often including them passing out for a while, but sometimes leaving them immobile but awake. And cases like Lucci, where he was beaten unconscious and woke up in a hospital much later.

The fact that some people recover quickly from some beatings does not imply that all people recover quickly from all beatings.