Well…half or more of the problem is the settings…
3Delight likes ‘power of two’ numbers best…but whole, even numbers work fine. Odd, fractional numbers make it ‘work harder’,
Now, for things like Pixel Samples (X,Y) 8 should be enough. Shadow Samples of 8, or 16 should for most things, be fine. Gain and Gamma should be left at default values. Pixel Filter Width…default is fine, but they MUST MATCH…and overall shading rate of above 1 is ‘draft’ mode…a shading rate of .2 is ‘acceptable’ and down to 0,01 for extremely fine, final production renders.