Not sure how much this will help but simply picking the centre of each pixel is causing severe aliasing. Using a more random selection would resolve that (it wo

Not sure how much this will help but simply picking the centre of each pixel is causing severe aliasing. Using a more random selection would resolve that (it would get rid of the moire), but wouldn't prevent much noise. Some structured blue noise might help a bit. Alternatively you could try to use thicker rays, not sure how doable that is but that way you might be able to filter out some of the high frequency details (for the low resolution renders at least).