I'm currently writing a story similar to Black Widow's backstory from the MCU. Basically, people are taken into this place, trained as assassins, injected with special powers, neutered/spayed or whatever at age 16, and can rise through ranks. Is this too cliche?
No, it’s cool!
Everything's been done. What matters is your unique perspective. As long as you're not actively copying someone else's work, then you're fine. Make sure your character, your details, and your voice shine through.
Everything's cliché at this point, but it's only cliché because it's been used often. It works and if it isn't broke, don't fix it
It seems pretty original to me. And its all in the execution of the story where you can really express originality.