I can name in order the arcs we still need to have before the end, and I can tell you, there's several. Elbaf, Emptee Bluffs, Fullilead, Lodestar, THEN Laughtale/Void Century. I'm not sure Lodestar will be that long. It's probably just going to be the jumping off point for Laughtale, but that's still a lot to cover before the eventual end.

Actually this isn’t the final arc of one piece nor do i think the second one is since that will be elbaf, this is said to be the Final “Saga” of Op so be sure to expect more arcs