I am of the opinion that luffy’s. Final bounty will be 5.6 billion that doesn’t mean luffy won’t be much stronger than roger it just means that when luffy is final much stronger than roger he would either be dead or there won’t be a power to give him a bounty or the world considers luffy a hero.
My hypothesis
Luffy defeats bb and becomes the pirate king on par or barely stronger than roger
Then Luffy defeats the final villain and becomes the world’s hero
My hypothesis
Luffy defeats bb and becomes the pirate king on par or barely stronger than roger
Then Luffy defeats the final villain and becomes the world’s hero