My experience with Fortnite is that during gameplay, it rarely stutters, with most settings on EPIC, with AA and shadows set to high. The FPS drops often occur when leaving the lobby, and sometimes in the battle bus (which is usually around 60fps). I get frequent crashing during the loading screen. I get stuttering during the game only when I'm airplaying (mirroring the screen) to my AppleTV, and it can crash the game doing this, as this puts additional stress on the system, but I'm surprised how well this works.
I also only use windowed fullscreen mode 2560 x 1080, as fullscreen mode crashes the game often.
On Windows, I get about 75 fps, but the whole experience is a little smoother, and doesn't crash, plus I can overclock the graphics card a little.
I'm looking to change to an AMD card, as I understand that the whole Mac experience is just more responsive, plus when Fortnite crashes, it appears to be metal driver related. I'm running the latest Nvidia drivers and latest version of High Sierra. The older 'safe' patched driver (106 I think) crashes Fortnite nearly ever time I run it.
Your issue might not be hackintosh related, but rather a buggy Mac version of Fortnite. I've not had it crash on IOS yet, but then I'm quite bad at the game anyway, and trying to play it with on screen controls makes it even harder!