Upgrade would probably work. It's a tossup what you'd actually have to upgrade (Gem quality? Bigness?), but you'd get there.
I think your biggest problem is just that Amethyst's an Earth-native. She was born on Earth. She was born after the war, even. She's not hardened like Pearl or Garnet are, she's literally lived on a happy little planet filled with pointless life her whole life, and she doesn't need to eat, and she doesn't need to sleep, (but she can do those things anyway), and she's lived like this for thousands of years.
Of course she's immature. She's never had to grow up. Of course she's the worst fighter, she's never had to go to war.
From a race bred for war and conformity, hers is kindof a pointless existence.She's also aware of this, and has kindof a complex about it?
The show would say something like, "That's beautiful tho, because she can be anything she wants to be!", and while I'm inclined to agree to some extent, it's also kindof sad that she, like, BARELY holds it together when people actually do need her to do shit.
Like there's a difference between choosing not to do things and being wildly unsuited for/incapable of it.
Anyway, what I'm saying is, you're probably gonna have to do some kind of hell training or psychological pep talk or something.
Otherwise, even if you give her a huge body, she's still gonna be Amethyst.
Although the huge body WOULD make her physically stronger, at least.That scene on the beach, where she told Steven, "Everyone's always dumping their problems on you, but you're not responsible for them. You shouldn't have to deal with everyone else's problems. And I'm not gonna do that to you."
I thought that was really mature and sweet of her. From Amethyst, of all people.
But yeah, do some anime hell training.>>63905040
In Greek Myth I was a child of Kairos, because I've kindof got a thing for him as a concept.
Also, Loki from Viking Saga, of course.