Guzman's bounty HAS to be over 1 billion, he was the First Mate of Rocks after all.
Crocodile's and Mihawk's new bounties are statements to that as well.
thx for the chp and about Guzman I feel like he might be a loyal and a good guy like Newgate.. it just might be becuz Xebec treated him cruely so he was bad🤔 it's my theory tho