Give Your Character Some Unique Characteristics
Even if your character was a beat-for-beat recreation of Katniss, you could still make her more unique by adding traits you know the original never had.
As far as I know, Katniss never showed a love of science in the books. Perhaps, in contrast, your character loves the science of the time and wants to learn more about it. They might also be a book nerd.
I am assuming you have read the Hunger Games books or watched the movies at some point. Is there something about the original you did not like?
Did you think she was too impulsive? Then make your character more cautious and careful. Did you believe Katniss should have been more deeply involved with the plans unfolding around her? Make your character a cunning strategist who is always one step ahead of their enemies.
Rather than simply copying the original, you can improve upon the original. Learn what made Katniss work, and then think about what could have been done better.
Then add some unique quirks of your own so that you have some plausible deniability. Does Katniss know how to play the violin? No? Perhaps your character should pick it up and learn she's quite good at it. Katniss always seemed to hate all the fancy dresses the Capitol put her in. Maybe your character unironically likes getting dressed up for fancy events?
Katniss was a rebel and a survivalist. In contrast, your character would be a scholar, a musician, a scientist, a strategist, a magician, a soldier...
Honestly, one of the core traits of Katniss is that she is a rebel, so if you want to truly make this character the opposite, have them play everything by the book.
It's up to you, though. A unique trait can be almost anything, so go wild and you'll be surprised how unique your character will become.