I would like to discuss the quality of the official Fairphone 4 Screen Protector with Privacy Filter.
From my point of view, it has a negative influence on the screen quality.
My screen has small black stripes in it. They have an angle of about 20 degrees with respect to the horizontal pixel rows. This leads to an unpleasant Moiré effect. Especially for small text, it is much harder to read them.
In addition, the screen does not complete black out on when the phone is tilted sideways. So, I buy an only half present privacy filter with a deterioration of overall screen quality.
I also see the black stripes with an angle of roughly 20 degrees. I also see the Moiré effect. I can confirm that it degrades screen quality by a lot. At first I thought that this would be caused by incorrect (slightly tilted) placement of the screen protector but I’ve tried moving it slightly and the situation did not improve, instead it only got worse.
In my case, the screen does almost completely black out when the phone is tilted sideways, which I find good enough.
I guess I will contact official support about these issues. They shouldn’t be selling such a low quality screen protector for that price. If it would work fine, the price would be ok, but this way it is not.