Bliss indeed, iPhone LCD's display 0 flickering according to that link "Devices listed with a "0" did not show big brightness fluctuations in our measurements". If someone is getting headaches using one of them, then they need glasses - not an endless nit-picking hypochondriac discussion on the internet.
People love a bandwagon, 'radiation' from phones, allergy to EM, and now sensitivity to PWM - despite Pulse Width Modulation being used in every LED manufactured since the dawn of the Light Emitting Diodes (It's how you emulate light, you turn it on/off very quickly and it gives the illusion of light). Alas, 2018 people are finally waking up and developing a problem with it. *Shrugs*
. On the plus side, it's just a headache now and no longer causes square eyes or blindness, so that's progress I suppose.
A very slow pulse creates a strobe effect, which is known to cause epileptic seizures in some people. But a fast pulse is imperceivable to the human eye. Heck, all light sources flicker, get out your phone and go film some lights in slow motion - street lights, TV's, monitors...
I'm in no way ignorant of how these things work, but I am blissful in my confidence that next year it'll be something new for click-bait susceptible people to discuss within a bias reinforcement loop.
Anyway, all I mean is just buy the phone/product you want and enjoy it. If you develop any biological symptoms when using a device then visit a doctor - not the MacRumor forums