"Phase" "Arc" "Journey"
Multiple statements and words have been made/used.
Here's the thing, story "arc" in Japan means something different than it does in the west. When we define "arc" we consider it to be localized to an island mostly. We use other western terms, usually "Saga" to determine longer story arcs.
Japan really doesn't use this the same way. Oda, his editors, and Jump in general, has used the term "arc" to describe the entire Yonko plot from Fishman Island. 四皇編 or Yonko Hen, means Yonko Arc. It's also used to describe individual "arcs" as we know it.ワノ国編 or Wano Kuni Hen is Wano Country Arc. Essentially the term is used interchangeably between both.
But one important thing to note is that we fundamentally can't be at the final arc by western definition after this. We haven't been to Elbaf, nor have we gotten the final road Poneglyph. These are fundamental truths since the story has set up motion to achieve and visit those things. Laugh Tale is probably separate from the final war. Geographically it's not the location where I'd expect the entire world would fight to take down the World Government, right?
And that is why, imo, its clear that what Oda is trying to convey here is the term "plotline". The Yonko "plotline". The story is in/nearing its final "plotline". The final war just can't start. It requires buildup. It requires time to escalate.
And that is also the reason why I think this going to essentially be the 2nd half of the New World. It will be the final "plotline" or "arc", it will feel like we are heading towards some sort of end, but it will also contain several smaller arcs, as the Yonko arc/plotline did before it before culminating to Wano.
Essentially what i expect next is our Punk Hazard type arc. Something to sink our teeth into setting up the end for the series. Then I expect something a bit bigger that addresses more content. Then something else potentially. Finally culminating to the end of Luffys Journey, Laugh Tale, and the final war.
Tldr: The end plotline can last 400 chapters and 10 years and you and I will love it.

[automerge]1630649707[/automerge]
Easy, it'll take him 10 years behind schedule lol. Final phase won't stop him from writing everything he wants before finishing. Wano is proof of that considering how big it is, even if he's allegedly "rushing".
[automerge]1630650039[/automerge]
Think about it logically. There should be at least 3:
- Elbaf
- Laugh Tale
- Final War
We know the warfront for the final war is probably Mariejois/New Marineford/Fishman Island, considering FIs destruction/Noah, Shirahoshi, Im, etc etc. So that can't be near Elbaf or Laugh Tale, which may be large or small arcs, who knows.
But then factor in any other potential arc beyond this.
- Lodestar (the last island in the new world, will we go there?)
- God Valley (Oda teased its significance and the WG made it disappear from maps, but never was stated to have actually been destroyed.)
- Vegapunk (is he separate from the final war? Will Kuma's plot be resolved prior? SSG?)
- Underworld
- etc etc etc
I think its safe to expect at least 3, with the potential to see a few more as possibilities, large or small, depending on what Oda wants to address before the end.