1 - It comes from the graphical displaying.
So it could be either hardware graphical related (aka GPU or display) or software graphical related.
2 - It doesn’t seem to come from driver or software issue since Windows didn’t work.
So it’s surely related to hardware, display or GPU. If it’s a desktop as other said you could try to change the output port of your display on your GPU…




Buy them an old PC and set them CasaOS for example