@Gurm I never had strain after updating a phone to a newer firmware/rom. My HTC one M8 was running on Marshmallow, but because using a custom ROM (Viper) I am not shure if I upgrade the Firmware with the Marshmallow ROM. It is possible to run the Marshmallow ROM on Android Lollipop firmware. The question in that case would be, what cause the dithering ROM or firmware?
Since 2 weeks I am forcing me using a Pixel 2 XL, because that is the phone I like to use. Independant of the straining phone I choose there is no big difference in strain strength. I see no solution for a solution in the next future. Every current device strain me. :-(
On desktop I use and Dell U2412 with Ubuntu 16.04 without any strain. But I recognized that current PWM free IPS-Panel like Eizo EV2455-BK also causing me strain. I am not shure if my Dell causing me a little strain running Windows 10 or if it is just because reading in the forum something about different os can cause strain or not? :-)
Of course you can count on me funding for more research so get a solution for the strain.