I play League of Legends and Valorant. And why don't the games from Riot Games consume a lot of CPU and GPU load? But Fortnite already?!
Because they are better optimized and less expensive to perform.
OK. And why didn't Epic do it that way at Fortnite?!
Eh, no. Valorant and League of Legends have a much simpler physics engine. It's easy to have a few more FPS. The Unreal Engine is btw in both games.
Riot put a lot of emphasis on performance, especially at Valorant. In addition, Fortnite has a much higher visibility and there are more players in the game, which of course increases the computational effort.