It doesn't seem likely that a game called Fortnite 2 will be released in the near future. Epic Games is currently investing heavily in Fortnite's technology. The game already uses Unreal Engine 5.1. There's no need or expectation for a new game to be created from scratch in terms of service, mechanics, or player community. From a marketing perspective, the additional hype that the Fortnite 2 name would bring doesn't make sense right now. Therefore, unless there's a significant surprise, Fortnite won't have a stand-alone sequel.