That show was about older woman and younger man.
If in Hamza's show, his love interest would be elder to him then I think yumna would be perfect for the role otherwise they'd look like elder sister and younger brother.
I think he might making the dobara type storyline


if they are not getting good numbers in pakistan they would miserably fail at box office. Still saba and sajal have actually proved their craft with Mom and Hindi Medium doing good in the movies + at box office.
ya toh people want that particular actor to be paired with men who are elder or they want her to be with younger men. Age appropriate casting
Because no way sajal would ever do that, she is above all these , very saint like 

. . .
363