Disable Shadows , Lumen , Nanite , Ray Tracing , and Motion Blur . These are the heaviest resource eaters.
Disabling Memory Integrity (under Device Security) can provide an instant 5–10% FPS boost, as it removes a virtualized security layer that slows down the kernel. How To Get MORE FPS on Low End PC (Fortnite FPS...
Windows is often optimized for office work, not gaming. You must "force" it to prioritize Fortnite. Disable Shadows , Lumen , Nanite , Ray