I've tried several cheaper cables for the Atomos Ninja Inferno, even ones that are recommended as 4K 60p. However, it seems the only one that works without any glitches or blackouts is this one from Atomos.
I use this one for the Sony A7ii. Also tried it out with an adapter for my Blackmagic pocket and it holds up to a good standard, full-sized HDMI to HDMI for the GH5. Trying other cables on both bodies had blackouts until I used the actual Atomos cable. the only issue is personally how stiff the cable is. i know its to keep it from damaging but just feels uncomfortable while i try to move stuff around. all in all an amazing piece of cable to have.