How did Anushka go from NH10 to Zero?

NH10 was a superlative performance and she got the nuances exactly right. On the other hand, her act in Zero was one of the WORST performances of 2018. She messed it up big time and didn't get the basics even right.

How does an actress deteriorate so much in a matter of few years?

Discuss.

So what, have the best actors not given underwhelming performances after giving their career best? Why single out Anushka. It's very natural, since an acting performance is a result of various factors falling into place.