it's not that she wants her sister to stay, she just doesn't want liefe to be happy. that's the reason she did all this nonsense.
as for the translation, i saw one of the translators was called "gemini", and i hope that's just another person, and not google's ai program gemini
by wengui's logic, su luxia also did nothing wrong. she simply used people to advance her own powers the way those 4 did. they should also be grateful they died helping su luxia ascend