looks like chroma macroblocking. you can try in after effects. add adjustment layer transfer mode color with effect median blur. this will blur the chroma. you can luma matte with find edges to only blur the macro blocks. the high end video cameras use a low pass optical filter to block IR leak, moire, false color, etc. you can try to reduce sharpness, but anything shot at the sun probably won’t work without buying rawlite.