Actually hard to tell.
Killer got 1 hit on Kaido and then beat Hawkins, who's hyped as "member of the WorstGen. (so far). But Killer is also the Right Hand of Kid, who, together with Law, will take down a Yonko. That alone should also inflate his bounty.
Sanji is gonna beat a 1.32B Calamity who was also part of Vegapunk's old team. (so far).
I don't see what else Killer is gonna do aside from keep fighting some fodders. But Sanji? Who the fuck knows what's gonna happen after.
Gotta be careful to not spoil anything. This thread should have been made tomorrow, IMO.
I believe there are genuine arguments to either side.