I also saw in a YT tut that 4k and 8k mean nothing as far as Resolution or quality of render goes but it does affect the DoF. Resolution is set by --ar 16:9 or 9:16 or whatever and 4k or 8k will affect the Dof of objects in the nearfield. Quality is --q 2 or 1 or 5 which is experimental and may not work the q# will affect render time  for fastest render I usually use a q of 2 seems to be good

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