As far as I know Napoli are currently not only aiming at Jack Grealizing, Napoli are currently focused on the two English League stars like Jadon Sancho (Man United) and as you said Jack Grealizing (Man City).

Nevertheless Napoli management still considers and is not rash to make the decision to carry out the transfer market this summer, the Italian League, considering that the two between Sancho & Grealism can bring different risks and potentials, one of which is Grealizing entering the age of 29 years and salary, From my observation it seems that Napoli management prioritizes Sancho, for that we will see who is included in the Napoli choice in the transfer market this summer.