@Najah_Ayache Welcome to the forum.
You cannot tweak the graphics in any way on these watches.
It is possible to change the DPI if you have root access but that is not the issue here and root access is a can of worms.
Ok, so the black line went away after a factory reset. This is very good news indeed.
Can you take some photos of the issue and email them to me at zappa1.pf@gmail.com please?
I have not seen this blurry screen issue before.
Normally there are lines or dead pixels…
I am also interested to know if you can see any condensation in the camera lens.
I ask this because we have seen a couple where they had condensation on the first day of opening the box. But only 2 as I say.
There is a reasonable chance that flashing the firmware will help you in this case.
Of course, without seeing the pictures I can’t be sure…
Here is the firmware thread