I have a problem with my XG438Q.
I have have had this monitor since 2019 then yesterday the video started showing double images in the vertical position.
This was for the entire screen. Makes it look blurry but really the text was doubled right above itself.
This would occur every 4 seconds then clear up.
I tried different cables in the display port and different ports on the video card (3090).
I also tried using one of the HDMI ports on the monitor and video card all with no results.
After a few hours, the top started folding over or compressing right at the top, again every 4 seconds and then clear up.
That kept getting larger and larger so it was about 1/3 of the top screen.
I used to work on TV's years ago and it looks like a problem I would see with a vertical circuit. However, todays monitors may now have the same type of circuits.