Or it could have catapulted her to stardom without the uncomfortable race issues and Scarlet's wooden acting hanging all over it

The role was literal whitewashing. They took an asian girl and literally made her white. That's fucking racist garbage.

So sexual harassment isn't a crime?

Everyone non-white in America is also accustomed to seeing (only) people who aren't them on screen.

If she can be anyone, then why is she white?

They already changed so much of the story for this movie so why couldn't they have cast a Japanese-American actress?

"American actress" does not equal white actress.

When Lex Luthor became president, Talia took over LexCorp and she was actually addressed as Talia Head.

I believe in her upcoming solo series, she's off to college so it wouldn't be hard to age her up to her early 20s

Having an "ethnic" character whose powerset has nothing to do with their ethnicity is pretty novel and something to rally behind.

If you can make them look like anyone, why are they all white? This is the whole problem. Why is white the default for everything?