I'd do Islam-Gaethje next because it's a fresh matchup, but I don't think that's a particularly close fight. Islam might not be quite as good of a grappler as Khabib, but I think he'e more than good enough to slice through Gaethje on the ground. And he's a better striker than Khabib. Gaethje's nothing more than a puncher's chance IMO.
Volk-Topuria is next, but I don't want it in January. Give Volk some time to recover. Don't want Volk at 80% or whatever.
I want Strickland-DDP next. Chimaev didn't do enough against a blown up WW on short notice to earn a title shot. Especially without having much of a resume at MW to begin with. And especially, especially since DDP finished Robert f***ing Whittaker.