To me it feels like all of this is leading to Fullalead with Egghead being our Punk Hazard (intro arc) and Elbaf being our DR/WCI (middle arc) and Fullalead being Wano (climax arc) essentially.
Kid had the 2nd longest pick from Wano, meaning Elbaf should be next or at least before Fullalead if thats where Law was going. Elbaf could focus mainly on giant/sky/moon lore, eventually culminating into one big incident with Blackbeard at Fullalead potentially.
Plus, it almost makes sense Fullalead is "Final" island before Lodestar. If you think about it, many great pirates probably reached Lodestar and learned about the RPs, but were left at a standstill at that point. That would mean you have tons of pirates just unable to do anything else, so they converge at Fullalead.
You also have people like Jean Ango (the bounty hunter from DR) mentioning that all of the Level 6 inmates from Impel Down all went somewhere, which could suggest this island too.