ublock is (mostly) best used as a blacklist filter while numatrix is best as a whitelist filter. you can toggle js, xhr, frame, etc for individual domains and sites with numatrix. similar function isn't impossible to achieve in ublock (which is why gorhill stopped developing umatrix, the origin of numatrix) but it's far more intuitive with numatrix. i suggest you just try as it's fairly easy to understand.