I think if Epic dropped the lawsuit after they lost the court case then Apple would let them back in the App Store. Continuing to fight makes it seem like there's no reason for Apple to reinstate Fortnite.

  [1] https://www.macrumors.com/2021/09/13/epic-games-files-appeal-against-apple-ruling/
  [2] https://www.macrumors.com/2021/09/22/fortnite-not-returning-to-app-store-until-legal-battle-ends/