My guess is that it is related to the video card and the drivers involved to set up the hackintosh. If I understand correctly, Final Cut Pro is optimized for the stock graphic cards available in Real Macs.
I too have an hackintosh that I use for Final Cut Pro but I picked a laptop with the same graphics as a standard mac. I don’t work with 4k so I have no useful information to answer your question.
Kirk Pitts.
video amateur.
Personal skateboard and band historian. 😉