I haven't any power saving issue with my LG5K monitor.
After update NvidiaGraphicsFixup and CoreDisplayFix from aerror my monitor works at real 5K like a charm!
With previous and latest NvidiaGraphicsFixup 1.2.6 the system reads two monitors LG UltraFine Display.
Only with custom NvidiaGraphicsFixup from aerror my system read the one LG UltraFine Display correct and works perfectly at real 5K.
I haven't any other problem with power saving or camera and USB ports.
Also in my home Hackintosh, I have the Dell DELL UP2715K and after update with these 2 kexts from aerror I solved the
mouse point issue and the "switch off and then on" issue after any boot!