Lodestar is most likely next. Luffy seems to be going to the islands that Law and Kid were going to after they left Wano in chapter 1056. That's...probably Lodestar? We don't actually know for sure where Law was headed to before Blackbeard ambushed him. It's hard to say for sure. It would be interesting if it was the remains of God Valley, but that was erased from the map, so that can't be it. I can't really think of many other islands we'd have to go to before the end of the story that would be between Elbaph and Laugh Tale, though. Running into Blackbeard here could serve the same function as going to Hachinosu. So, that might save us a little time.
Hachinosu is a possibility, though. Robin still needs to get the last Rio Poneglph, which is most likely currently on Hachniosu. So, either they need to save Pudding from Blackbeard since Pudding will likely read that Poneglyph, or they need to go to Hachinosu to have Robin see this last Rio Poneglyph for herself, or both. The problem with going to Hachinosu at this point is that if the Rocky Port Incident happened during the timeskip, that kind of implies that Hachinosu is located closer to the beginning of the New World, rather than almost all the way to Laugh Tale. Chances are, Hachinosu is nowhere near Wano. It'd probably be closer to Fishman Island.
https://onepiece.fandom.com/wiki/Rocky_Port_Incident
Running into The Man Marked By Flames is another possibility. I could see them doing that after leaving Elbaph so they can get the last Road Poneglyph. That's not exactly an "island", but I could see that being the next arc directly after Elbaph. Especially if Scopper has more information on The Man Marked By Flames to share with the Strawhats before they leave Elbaph.
I think those 3 are the most likely. But, lets run down a few more of these possibilities.
Doing something with the Revolutionary Army would be nice. But, they're currently occupied with their siege on Mariejois. So, I doubt any Revolutionary-controlled island will likely be important enough to go to for a whole arc. So tthat likely rules out Vira.
New Marineford likely has the same problem as Hachinosu. It seems likely that it's located closer to the start of the New World rather than deep into it. It has bubbles around it like Sabaody, so it's probably closer to that side of the world. We haven't seen much of a Marine presence around Wano, so I don't think one of their major bases is around here. Same goes for Impel Down.
Mariejois would make for a exciting arc. But, unless the Strawhats find a way to use the Gods Knights' summoning circles, that seems unlikely. Mariejois is basically on the other side of the world from where the Strawhats currently are. Although...I will point out that you need a "Mark" to use the summoning circles. Which seems to be on the Gods Knights left arms. And...Nami just so happens to have a tattoo on her left arm. So...maybe Nami and Nami alone can actually use the summoning circles? That's highly unlikely. I'm not sure why that would work, unless they happened to use the same kind of ink for the tattoos or something. Unless the Mark is tied to the Slave Brands, since I imagine it'd be tempting to transport your "property" using these summoning circles. But, it would be a interesting sub-plot, watching Nami try to sneak around Mariejois all alone.
Sphinx...is technically possible. We know from Marco that it seems to be really close to Wano, like Egghead and Elbaph seem to be. It would be nice to visit Ace and Whitebeard's graves. It's just that...Sphinx is kind of boring? I don't know if there's a burning NEED to go to that island. We need to follow up on Weevil and Buckin, but he's already been captured by the Marines. If we go there it'd probably be a VERY short arc. I'm just not sure about this one. It could make for a good prelude to Lodestar or Laugh Tale, though.
As for the Moon...hmmm. It would be fun to go to the Moon and see what Enel's been up to for the last 2 years. And I do think we'll end up at least seeing Enel before the end of the story. I'm just not sure. I have a hunch that the endgame of One Piece will have more to do with the core of the planet and the Underworld implied by the Mural, than the Moon up above. I think we're more likely to go DOWN, not UP. But, who knows? It is possible. And it's possibly the most exciting possibility here. I don't think it'd be NEXT. Maybe if the Strawhats get teleported there during Laugh Tale? Like, if they find some advanced kingdom's spaceship on Laugh Tale, they may get teleported up to the Moon to do something to save the World and stop the flooding? Or if the Strawhats end up stealing Uranos from Imu. That's a possibility. But, I think Lodestar at least would have to come first. The Moon feels like endgame territory, if we even end up going there at all.
If it turns out the next stop is Lodestar, I think we're going to be VERY close to getting to Laugh Tale and the endgame of this story.