I am more interested in the assumption that Kaido can be harald's son.
They seem so similar in appearance that I cant see how they arent, and considering what we learned about Buccaneers, it wouldnt suprise me if Oni are just the same but with Ancient Giants.
We know Little Oars Jr was the last true ancient giant, but Oda then made Harald and Loki showing that their bloodline still exists between regular giants, and Kaido is roughly the age that Harald was sailing the world
The FB last chapter went from 63 to 56 years ago, which Harald was confirmed to be traveling to the Reverie that year (cause then it skips to 48 years ago when Rocks arrives). Considering he wasnt allowed to be with Ida, and he mourned Estrid's death 63 years ago, Kaido absolutely could have been his son born 59 years ago.