Leaving aside the narrative and powerscaling counterarguments, I'm not sure the story actually allows Sanji to have a solo battle against any of the Calamities.
On the Alliance's side, we'll have:
- Zoro
- Marco
- Sanji
- Nekomamushi
- Drake
- Hyougoro
- Kawamatsu
- Izo
- Chopper
- The Yakuza Bosses
On the Beast Pirates side, we'll have:
- King
- Queen
- Perospero
- Apoo
- He might defect or even go solo
I'll try and present the best-case scenario for Sanji:
- Hyougoro and the Yakuza bosses deal with fodder or recover.
- They don't fight anyone of note.
- Nekomamushi fights Perospero
- Chopper treats Zoro
- Drake fights Apoo
- Marco (or Zoro + Izo) deal with King
This still leaves at least Sanji and Kawamatsu to take on Queen.
And honestly speaking, I don't expect this to be how it shakes out. For entirely separate reasons, I doubt Zoro β even a brutally injured Zoro β would tag-team a swordsman with another one. FIghting despite injuries that would cripple anyone else is his entire shtick.
Exhibit A:
Exhibit B:
Exhibit C:
There may be others, but this isn't supposed to be a Zoro thread, so I'll stop here for now.
I also don't think Drake will fight Apoo. Queen backstabbing and discarding Apoo was really highlighted, and I got the impression that Apoo was reconsidering his entire allegiance to the Beast Pirates:
So I'm actually expecting Sanji to face Queen alongside some combination of (Drake, Kawamatsu and Izo).
Perhaps I'm wrong on Zoro and he'll face King with backup from Izo, and I'm wrong on Apoo and he'll face Drake, but that still leaves Kawamatsu unaccounted for. Ultimately, I don't think there's a viable configuration of matchups on the Live Floor that permits Sanji to defeat Queen solo.
I expect Sanji to land the last hit, and maybe his support would be defeated along the way and the match would end in a 1 vs 1. I can see a Doflamingo vs Luffy and Law situation being plausible. That still isn't a solo match though.