Considering Cross Guild is poor as fuck, 3 billion is literally an absurdly high bounty for the Admirals. Literally this crew just obtained one fucking ship lol, compared to the Marines who have thousands of warships and exponentially more resources than Cross Guild does.
The worst thing you can say about a 3 billion bounty is that the Admirals have bounties on par with three guys that took down Big Mom and Kaido. The best (and most accurate) thing you can say about these bounties is that 3 billion is an absurdly high for a poor organization that doesn’t even have two ships to its name lol.