Depending on how much "stretch" you want, here are the top picks for 16:9 monitors:
The "sweet spot." It provides a slight boost in FPS and visibility without making the game look too blurry or distorted. Fortnite Stretched Resolution: Best GameUserSet...
You must also create a Custom Resolution in your GPU control panel (NVIDIA Control Panel or AMD Radeon Software) that matches what you put in the config file, or you'll see black bars. Depending on how much "stretch" you want, here
Want to get that extra competitive edge? Switching to a in Fortnite can improve your FPS and make player models appear slightly wider, potentially helping with your aim. potentially helping with your aim.