degen Super interesting. I don't have a Dasung to see if this correlates with my strain or not but it would be good to find "safe" colors and see if using exclusively those would help. But it seems it's not as simple as "light and bright ones are dithered...dark and greyish ones are not".
I use Redshift which is an f.lux like application so I would guess it's probably making it worse just like yours is but the question is why? Someone else mentioned adjusting gamma at all caused them strain and color temp apps do adjust gamma...on the otherhand another person mentioned a proper icc color profile helped them and those create a custom gamma. Whether or not this dithering is the cause of the strain or just a red herring reamins to be seen but its obvious dithering is pretty common now.
Does it strain you on the Dasung like LCDs do, or it's just a noticable annoyance now that you see it? Also as KM asked can you test other OSes like Linux from a live USB etc? It's very simple to do if you have the time. Also there is surely a way to connect phones to the Dasung as well so that would be interesting to see what Android and iOS are doing.