Sir we have shared history no denying from me, But the shared history only starts after Ghauri invasion,
My source is Indus Saga which doesn't mentions anything about gupta rule, pala rule in pakistan, The book says pakistanis are different from indians, culturally, historically and ethnically.
We share only 500 years of shared history in the past 6000 years.
Our culture is again mixture of indian, arab, afghan and turkic while your culture is mainly indian.
Pakistan is just a mixture of different cultures and people.
I request you to buy this book Indus Saga and all you questions will be answered
Amazon.com: The Indus Saga: From Pataliputra to Partition (9788174364210): Aitzaz Ahsan: Books