Ok, cool. I am from austria. "Good" to hear that there are also some eyestrain people from mid europe.
"What is the reason why you cannot breath through the nose then, if I may ask?" How did you mean that?
My orthodonist said, that strained muscles from the TMJ could cause this.
I hope that without the strainend muscles in my face (I described my therapie much more exactly in some posts above) the pressure on the eyes will decrease and so the eyes can focus in the right way.
Long story short: My theory is that your eyes have learned to focus right at the old smartphone screen, but can't at the new one. A binocular eyetest showed that I've problems to focus on things which are moving right to me - however I've never had any problems off a screen.
Same at my side. I've tried so many setups, so many different drivers, so many smartphones, so many different TVs. I've never found the technical solution for this, so I tried to come up with a health solution
Since many of us also suffer from grinding their teeth, sinusitis, TMJ, sleeping problems, ENT problems....there just has to be a connection between those many symptoms.