First of all, thank you very much for your interest in the problem I'm experiencing. I was wondering if these horizontal lines could be water marks. Because I always clean in the same direction, which is horizontal. But unfortunately the situation doesn't seem to be like that. And I'm really thinking about what I might have done wrong, but I can't find an answer. I even choose the water I use carefully so that it contains no or minimal minerals. I do not apply any force while cleaning the screen. Since I thought that the most compatible and non-damaging material for this screen would be Apple Polishing Cloth, I cleaned the screen with this cloth. By the way, these scratches are not visible / don't attract attention in normal use. But If I'm in a place with intense sunlight, I can see these marks clearly.
It's not really a 'what you are doing wrong' thing. We know there's not really a generic problem with the screens, or there would be very widespread complaints. Asmuch as many might not notice, most would.
So what we have, I think, is an issue of something in the environment, which either exists in the locality and causes abrasion or something in, or on, the cleaning cloth.
Examples of the environment would be things like particulates in the air - the Canadian wildfires in my location last summer/autumn were a very notable example, which caused heavy abrasion on surfaces - but could also be particles in household dust and deposits which have collected in the cloth. For the cloth, even those designed for this kind of use could become contaminated, and water or IPA wouldn't help other than to suspend the contaminants while the cloth is used.
What I'd want to look at is how, or by what means, the relatively soft surface of the screen could be cleaned and restored. If it's scratching to the nit-glare coating, it probably can't, but surface scratches on the panel itself may be ameliorated to some degree at least with cleaners and refinishers.
