for fortnite, you can do any custom res you want, mine's set up but it does not seemingly affect my DFLW, but still, maybe worth a try, you can learn it from one of jerian's video, perhaps this one:
https://www.youtube.com/watch?v=a5vq...nnel=itsJerian
besides that, i dont know, just play on 1024 and download the borderless gaming to fullscreen it?