i was looking at this formula to calculate the correct aperture to match fov witch csgo

i got the value of 1208x680 but since fortnite is horizontaly clamped, instead of 680 can i just use 1080 and get the same result but with a bigger fov?

Could be wrong, but pretty sure Fortnite is horizontal clamp only if the aspect ratio is less than 16/9. It's then 16:9 clamped for wider aspect ratios. This is why people use stretched resolutions, because they gain vertical fov and get thicker enemies. So you could do 1208x1080. Same focal length, but render the rest of the image vertically.