I think it will be Law
Pizarro tanked an ACoC punch from Garp. No SH bar Luffy and Zoro has that level of AP. And tbh I’m not even 100% on Zoro as he’s yet to split the sky while Garp rivaled Roger, a sky splitter.
Pizarro more than likely needs Puncture Wille level AP to be taken out. But if he can merge with Elbaf, the AP needed to beat him would be even greater.
Law vs Pizarro won’t be an extreme diff fight or anything, but it would wank the hell out of Law by letting him show off island level AP.
Alternatively Oda could give it to Kid, with Law rematching Teach before Luffy gets his 1v1. Kid needs a good 1v1 to restore his hype after the Shanks incident. Him busting an island, possibly with ACoC, would do it.
Lastly it could be Koby, but tbh I’d prefer him to 2v1 Kuzan with Smoker.