This shows plot is rocky.
When Varian asked Rapunzel to help fix the problem with the crystals she waits over several episodes to do so despite the fact they were all just fillers. And her and Cassandra had a great relationship be all of a sudden Cassandra turns evil.
The first excuse was she was Gothel's daughter but she was raised by the captain and didn't even remeber her mom until a floating blue child showed her; Futhur more she was abandoned by her and knew how badly Rapunzel was treated for god sake she was used for her hair and isolated her for years and Rapunzel was miserable; And she would have died quickly anyway because she was old and would've left Cassandra with tramua still. After hearing how Rapunzel was treated she still used it as a excuse to turn Cassandra evil. So basically "MoMmy LikES YoU MoRe So I'm TRYinG tO mAke yOu MaD!"
Also at the end they were there to finally netrualize the dangerous rocks so they wouldn't be a threat anymore. If she was jealous of Rapunzel's powers that still isn't a excuse because in exchange for netrualizing the rocks she was going give up her powers voluntarily give up her powers, then they would be equals.
Finally, doing it for power wouldn't make sense if she's trying to rule everyone, because everyone would die because they failed in stopping the rocks from killing everyone. So what's a kingdom with no subjects?
She also said "its just my destiny so I'm not a bad person" but she threaten to kill Eugen, acussed Rapunzel of murder even though it was just self defense, threaten more people, getting upset when people try to defend themselves against her, turning them into statues, nearly crushing all Rapunzel's friends, kidnapping Pascal and Varian, harming Eugen, threatening to destroy an entire libray of magical books, leaving Rapunzel to die of poison gas in a cave, ect. You get the picture. Maybe just a thought, that makes you a horrible person .
Also why is everything about destiny everything done was choices made by others, the king choose to save his wife by using the magic flower. Eugen grinded his way to becoming chief of the royal guards. This was ALL choice yet Cassandra is over here like "Idk who I am so I'm just going to find a destiny". But saying she doesn't know who she is, fighting by Rapunzel's side and also before Eugen trying to become chief of the royal guards. Seriously being so pasionate about fighting, it's "IdK WhAt I'm GonNa dO NexT" ? I call bs. Anything would've been better than her saying she doesn't know herself just because, not even like Steven Universe where Steven actaully has a identity cristist because SHE DOESN'T.
So after all I said if you don't mind that go ahead watch the show be my guest.
(But one thing I'm not going to do is be a salty christian and hate on it because there's magic in it. That's just wrong.)