Oda is feeding us pieces, but this one is easily explainable through Chekhov's Gun principle.
In this chapter Vegapunk explains to Bonney that the "people are waiting for hundreds of years for Sun God Nika". This is established in the story and the giants are the oldest living species in the world of One Piece, they can get above 300 years old. There are certainly giants in and from Elbaf that are awaiting the return of Sun God Nika as it has been foreshadowed with the Solar Solistice on Elbaf, that festival in Elbaf where they were fasting and sending prayers to the Sun in Linlin's flashback story. Nothing of this is comming out of the blue and it will all just be deepened in the future arc that is Elbaf.
We also had Dory and Broggy be with Shanks before, and the Nika form wanted poster is spreading. They certainly want to invite Nika to Elbaf imho.
Rest your mind fella, this was well written, most readers just were not able to solve this riddle. I also haven't seen this comming. But you know who predicted this chapter?