The wano kuni arc ended with Luffy, Kid, and Law having equal bounties. This is nothing new, they have had comparable bounties in the past.
Now in regards to the current point of our story. We can assume that Elbaf will most likely be a big ensemble arc like dressrosa or wano. Saul is there, Kid is searching for Saul, so Kid will very likely be in elbaf. Law will also very likely be involved due to blackbeard.
So if Oda follows his formula(which he always does), Luffy will probably go into elbaf with a much higher bounty than Kid and Law, leave elbaf with equal bounties, and then do something that will put his bounty higher again(this will most likely be him finding one piece).
So what will Luffy do that will put his bounty above Kid and Law's by the start of elbaf? With what's going on in the manga, I think it should be obvious. Luffy will defeat Kizaru. This will either put his bounty in the high 3 billions, or even the 4 billions. Beating Teach will bring him to 5 billion. And then, finally, finding one piece should bring him to 5.6 billion.
- in sabaody, Kid's bounty was higher than Luffy's
- in dressrosa, Luffy's bounty was marginally higher than Kid's and equal to Law's
- Marineford and impel down put Luffy's bounty at 400 mil by the end of the pre-skip
- Whole Cake Island put Luffy at 1.5 billion by the start of wano
Now in regards to the current point of our story. We can assume that Elbaf will most likely be a big ensemble arc like dressrosa or wano. Saul is there, Kid is searching for Saul, so Kid will very likely be in elbaf. Law will also very likely be involved due to blackbeard.
So if Oda follows his formula(which he always does), Luffy will probably go into elbaf with a much higher bounty than Kid and Law, leave elbaf with equal bounties, and then do something that will put his bounty higher again(this will most likely be him finding one piece).
So what will Luffy do that will put his bounty above Kid and Law's by the start of elbaf? With what's going on in the manga, I think it should be obvious. Luffy will defeat Kizaru. This will either put his bounty in the high 3 billions, or even the 4 billions. Beating Teach will bring him to 5 billion. And then, finally, finding one piece should bring him to 5.6 billion.