What kind of artifacts? If it's black/flickering edges you can try to place a Smooth operator on your particles after the Voronoi Fracture.
Ignore Starting Penetrations is probably causing your stack of particles to fall down through the ground, because they're....ignoring starting penetrations (including those with the ground). You can use Particle Groups to filter what types of penetrations you want to ignore.
Not sure what you mean by your third question...
Ignore Starting Penetrations is probably causing your stack of particles to fall down through the ground, because they're....ignoring starting penetrations (including those with the ground). You can use Particle Groups to filter what types of penetrations you want to ignore.
Not sure what you mean by your third question...