Brother, whether the tiles crack or not has little to do with the drill bit, but mainly the tiles themselves. It doesn't matter how to drill the better brick (soft), but the worse brick (hard) is too brittle and particularly smooth, so it depends on what happened to the brick you used before ~!
One more thing, if you don't want to crack so ugly, try to remove the glossy surface from the place where you want to drill, which will be much better ~! !