Hi, this is not the issue that we are describing in this thread - the artifacts / grey wall we are describing appear on the horizon only and they are temporary, lasting a fraction of a second and normally when you rotate your head upwards (look up). You may not see them all the time as I believe they depend on cloud conditions, player altitude, and sun location.
Regarding your screenshot of a different problem (grey border at bottom of screen) I do remember occasionally getting similar borders at the bottom of the screen in my Quest 2 when I used Cable Link, but unfortunately I do not remember ever resolving it (I changed over to Virtual Desktop wireless as I found I got a sharper image and the image looked much nicer because it lets you reduce the gamma/brightness)