the main thing is that i disagree with most people
most people seem to believe will keep going for another 7~10 years
if Elbaf is 50~70 chapters, that means 2.5 years on that arc
let's say Egghead ends this year
this means we would be in 2027 by the time the war even starts
and the war would be like what? another two years? people say it has to be the biggest arc in One Piece and shit
if that was the case, One Piece is not ending before 2030
Hey, people can wish as much as they want for One Piece to never end, i get it
but honestly, i think it won't take that long
Based on Whitebeard's words, I think the final war will begin AFTER the One Piece is found, and that the One Piece is the trigger for it. This is why Roger and the squad couldn't do anything; they needed to wait for the world to be ready to go to war with the WG, which it wasn't. Now, the Straw Hats have allied many different nations, tribes, and pirate crews together, and can actually fight back.
So, I think we'll get:
End of Egghead (10-20 more chapters)
Wano Act 4 and 5 (30-35 chapters)
Elbaf (40-50 chapters)
Lodestar (10-15 chapters)
Laugh Tale (70-100 chapters)
Final War (100-150 chapters)
Epilogue (20-30 chapters)
Other possible arcs
Criminal Underworld Arc
Moon Arc (I think Laugh Tale is on the moon which is why I didn't add this)
So like... 300-400 chapters, 250 if Oda really does pick up the pace. 7-10 years, IMO.