Vergo was the first top executive shown, and he turned out to be the strongest. So Jack being the first calamity shown doesn't mean that he is not the strongest. The fact that Jack has a 1B beri bounty is enough to convince me that he is the first mate.
Bounties don't mean anything by your logic he should only be as strong as two aces lol..
Also that would mean that Moria was stronger then kuma And ace is stronger then doffy...
All I'm saying is that jack seems to b more of close combat kind of fighter which is why he has to use that cheap weapon if cannot defeat a person in close combat (said dukes -.-) someone like kuzan doffy potentially sabo (once he gets the Mera Mera figured out) they can keep the fight long distance.... Etc
All he has shown (which is going by that) is to be more of close combat which doesn't go well with kuzan... If can take off limbs in brink of second lol (Jozu)
Also Enel oda said had government known about him would be 500 million bounty at least ....
Croc if the government knew about what he was doing as an underground boss and taking over alabaster would be at the very least 300 to 400 mill bounty
Doffy himself with the worlds best underground broker supplying weapons to both sides (world g and yonko alike) taking over a kingdom and killing innocents and abducting 1,000's of ppl (the toys) some being marines and pirates hunted by marines so withholding them and information etc.. And don't get me started about how he was using the warlord system and blackmailing the Nobels etc his bounty would be at very least 750 mill prob 1 bill as well..
What I don't understand is why someone like law (age around 26 or so) had never heard of Jack despite his bounty being so high he must have done things note worthy to get that bounty unless it just comes from being under kaido I wonder what Marco bounty is ... Sorry for rambling point is bounties don't mean shit by his feats and how he fights at best he can push kuzan to a solid mid diff... Similar to Jozu doffy vista etc he can fight admiral level fighters but cannot win for most Part