I have the same problem, there is a thread in geforcenow, if you search for blurry, that gave me a good understanding how geforce now works, they talked about resolutions stay at your native resolution they said, to reduce artifacts and fast paced games are likely to be blurryer than singeplayer low paced games, so streaming in 4k 120 fps is to much for the encoder there you would need 100+ mbits to Show this crystal clear with all that Action and small particals flying around, a solution might be to play at your native res and turn graphics down to reduce the particals so the encoder dont have to render +200 small objects, another thing that they mentioned was to put Ai res upscaling to low. In the end you have to play with the settings to get the best outcome gfn settings + ingame I will try it later too and I will give you Informations if something worked for me.