Heritage: Indus or Islam
(See Last 3 Paragraph)
There are two modern interpretations of what pakistans heritage should be.
One is Ancestry. That the pakistani people are the direct and only descendants of the people of sindh, punjab, balchistan, kpk and kashmir, and by extension the civillizations of indus mehrgarh and gandhara etc. Even today Dravidian languages are spoken in balchistan separate by thousands of miles from south india. Indians are Not related by blood or ancestry to indus or gandhara and try to claim it as their history under the pretext of "india one country" while their ancestors were directly at conflict with and had wars with our ancestors.
The Other is Religion. As the nation was created solely on the basis of religion and Two nation Theory, Islams heritage is our heritage. This means Pakistan is the spirtual success of every islamic nation and history in the subcontinent, Starting from Muhammad bin Qasim, The Ghaznavids, Delhi Sultanate, all the way to the Mughal Empire.
Now to the issue; Indians claim pakistans heritage of indus is invalid because by adopting an identity based on the religion of Islam , its severed from the Beliefs and Culture of Indus. However that is a paradox because if Culture and Heritage can be changed and denied by an identity formed on a Religion, you can simply deduce Culture and Heritage can be gained by an identity formed on Religion.
Thus If Pakistan Is not the heritage of its own ancestors because of a religious identity, then by that same logic Pakistan is the successor of states like the Ghaznavids, the Delhi sultanate or indeed the Mughal empire.
And if Pakistan is Not the successor of the Delhi Sultanate or the Mughal Empire because theyre not pakistan's ancestors or their lands dont lie in modern pakistans territory then by the same logic Pakistan is the Successor of Indus because theyre their ancestors And their lands lie in Pakistan, and indias just pretending.
I hope you see now that denying one of pakistans heritage directly enforces the other by the same logic. I've seen indians claim Indus as theirs because same culture and religion of the people (when by that same logic pakistan is the delhi sultanates successor) and in the same breath deny Pakistans Muslim heritage too. Pakistan was made by Muslims all over india who migrated there so Pakistan has a claim to all muslim kingdoms in india by that logic. I hope you understand the paradox.