I'd say if it's Elbaf, then its in a capacity where she and her crew aren't fully viable threats. There's a "tragedy" element that comes with Caramel and her feud with the Giants. Not only that, but her actual dreams (eating food with people her size, having all races come together) are actually genuine and good dreams from her. With this, I can totally believe why Oda won't make her irrelevant or most of her crew, because because do still have a role to play.
But in that that note, I don't believe she'd be the main focus of Elbaf. I think this will primarily be reserved for either another Yonko, Vegapunk or entirely just the Giants themselves (i.e. Loki as a villain, which I doubt). There are also still unaddressed things like the escaped Level 6 convicts or Underworld members, but who knows how far those go. We don't even know where Kuma or Bonney or Urogue or Vivi, Revo's, 4th RP etc all come into play. Even Rocks as a concept isn't done after this arc.
This is why i dont see her being the main anything other than a big factor into the arc, whether as an ally or as a plot device.