This definitely ain't happening unless Luffy convinces BM and Kaido to join the strawhats.
IDK man by end of Wano Luffy will have (according to the news papers)
Power to fight and defeat Yonko's
Subordinates that can defeat Yonko commanders and executives
His Grandfleet
3 Road Poneglyh rubbings
A subordinate that can read said Ponelgyh rubbings
Legendary lineage and connections throughout the world
The Initial D.
Possibly a special DF
Wano Kuni under his banner
Laundry List of feats and accomplishments from the entire series
I'd say 5 billion is just about right with the right context/framing