I hate the pixelated DOF but I don't want to disable it either.
Looks like the DOF renders at half the resolution of rendering resolution, causing pixelation [It's still better than ignite engine, but it actually looks worse than FiFA 12]. graphics lua had some random values regarding DOF but changing those did nothing.
Do you know whether there's any lua file that controls the quality of DOF? DOF also becomes less blurry as you increase the resolution. At 4k it's still acceptable. But after few years, when we can bump resolution to 8k, the DOF will look hideous. So it's better to find whatever controls the blur radius of DOF.
I'm searching all the lua files right now, but so far I got no lead.
It is probably contained inside the DOF shaders and you won't be accessing those unless you have the ability to create/edit the shader coding.