please, could you tell me the way to check if my screen is affected? Any particular app?
Hold the Mini 6 in
portrait orientation with some lines of text displayed.
Scroll the text up and down by moving it up and down with your finger.
The lines of text will slant slightly, i.e., not remain exactly level while moving up or down.
ALL iPad Mini 6's will show this. (In fact, all devices have this, either landscape or portrait, but it is much more obvious on the iPad Mini 6 than most).
No iPad Mini 6 will be different from any other iPad Mini 6, they are all exactly the same, as it is due to the inherent way in which the LCD panel works.
An exchange will not help in the slightest.
Either you are OK with it, or you are not, in which case your only option is to return it. It does not bother me, but it is there.
In some ways I suggest not even try to look for it, and just enjoy the iPad.