Something big is supposed to happen to Sabo this year (and Boa). So, while technically he won't be in Wano, he will be featured in the Wano arc.
Its definitely the mid Act 3/Act 4 update as he's been doing. As such, I do expect Act 3 to end before chapter 1000, then we get the big updates for these characters before being thrown back into Wano's battles for Act 4.
Honestly, Wano has become my favorite arc purely for this type of setup. Oda totally knew he was going to be in Wano for a 100+ chapters (maybe even 150 by the end), so he used the Kabuki structure to deliver world news each time the Acts end.
My expectation is Act 3 ends somewhere around 997/998, so that way the next few chapters are bombshell ones with Sabo/Vivi/etc and we get back to Act 4 in chapter 1001. We are still on track to get there by the end of the year (only 3 actual weeks revolving around Covid delays), at least the late 990's.