We have plenty of evidence that yellow diamond is part of the diamond authorities. Her sisters were defeated by rose quartz, and with yellow diamond being infuriated, she seemed revenge on the earth. She created the cluster to hurt the earth, to break it, but peridot and lapis and jasper were caught, so they all know and want to stop it. Yellow diamond will eventually come to earth to check up, and start a war with the earth, but will not find rose. She will try to kill the gems, but doesn't known hat Steven is rose, and will be defeated, leaving Steven as the home world ruler. After all, Steven and his mother are the most powerful, and being the ones to defeat the diamond authorities , will become the ruler. That's just my thought, you have yours, and mine might not be true? But don't say bad things, this is what I believe.