Nah he won't be that high from that especially gap in bounty between Yonko and YCs especially. It's fitting his bounty is based on rivalry way more.
Lol you base that on Morgan saying Luffy is the 5th emperor? I doubt the marines take that into consideration when giving him his bounty..
Commanders like Marco and Beckmann probably have bounties above 1.5 billion,yet they aren't empeyrors which disproves the notion of king not possibly having a bounty equal to luffy's or above.
The reasons for king having 1.33 billion based on his supposed "rivalry" with Queen are very weak indications as;
1)how are the marines supposed to know they are Rivals ?
2)they were schooling jack in 925 together,but as we saw from the flashback those two are the most veteran members of beast pirates,so ofc jack will be below them in the hierarchy and is obviously weaker
As for their bickering, that doesn't tell us anything about their strength or threat level as in that same panel,king calls Queen a powerless fool for not being able to break Luffy and kid.
To summarize my thinking:
They are no emperor level bounties as there is a wide gap between BB and other emperors.
Marco as leader of remnants of WB pirates surely has a higher bounty than Luffy,so does Beckman (for red hair pirates having high average and balanced bounties,and comparing shanks bounty to Big mom and kaido,we clearly see shanks top 3 will have bounties at least around luffy's bounty.
King and Queen bickering doesn't mean they are close in strength or threat level for them to have close bounties.
Finally we will just wait and see but i'm going to remind you about this post when King's Bounty is revealed.
For me king is going to be at least 1.4billion.