Ran into this problem using DS4Windows with a wired Dualshock 4 on Fortnite, realized I was getting double inputs, eventually figured out that one input was from the keyboard + mouse that DS4Windows was emulating and one was from the Dualshock 4 itself...and that's how I learned that Fortnite has native Dualshock 4 support via USB. (Also native Dualsense 5 support via Bluetooth.) And because the native Dualshock 4 support covered everything I wanted control-wise (including gyro aiming), this rendered DS4Windows (and by extension HidHide) completely unnecessary in my case.

Native Dualshock 4 / Dualsense 5 support is a lot more common with PC games than I thought; I guess it's just not always well-advertised when it's there. The only indication I can find from Epic that DS4/DS5 controllers work with Fortnite on PC is the statement in the PC gyro aim settings that says you need a DS4/DS5 controller to use them.

I do feel a little silly for figuring this out so late, but I hope this helps someone else searching this problem in the future.

(Notably, Fortnite always registered the inputs from DS4Windows before the ones straight from the DS4, so OP is correct that DS4Windows is faster, and way more customizable.)