My external monitor got damaged and now it is showing 6 thin vertical lines colorful when showing a white background. I suppose at these lines a red, green or blue subpixel is permanently disabled. Now having bright colorful lines on a white background is a bit annoying. I would prefer to have small black lines instead. So, is there a way do turn off the remaining subpixels of those lines? I use an integrated intel gpu and gnome on wayland. However, I would happily switch to x11 if this is the only way to fix the issue.
If the monitor was physically damaged it may be difficult to solve by software. You may be able to check if this is cable, monitor, or GPU related by trying a different cable or monitor. If replacing one of those eliminates the error then that is the easiest solution. If the issue remains with both a different cable and monitor then it would seem to be GPU related.
I am not sure there is any easy way to solve this type of issue if there is physical damage to the monitor other than replacing the monitor. Possibly take it to a service center for repair? IME service may cost more than replacing it.
An advantage to replacing it is the newer and better options available now that were not possible just a couple years ago.
It certainly is physical damage, and I know this cannot be repaired by software. However, software could in principle help reduce the issue. Some subpixels are dead. If I could tell the GPU driver to turn off the corresponding pixels, then I would be left with some black lines on white background instead of bright yellow, magenta or cyan lines. I know this would work physically, because on a black background the lines are not present. That means the remaining subpixels are alive and can be disabled. The question is only how to tell the GPU driver to unconditionally turn off those pixels, regardless of the real content of the screen.
For clarification I have added a picture of a relevant part of my screen (sorry, screenshots don’t work for this 
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