We Pakistanis all share the same genetic cluster and have cultural similarities.
how come Mohajhirs are not a separate group ?
you have summarized it well but some major holes
They never went beyond Chenab...Big Difference compared to Indus....and the Post Mauryan Empires only extended as a small triangular incision beyond Jalandhar/Sutlej. This small triangular incision would include prsent day Lahore,Sialkot and in some cases Gujarat,Punjab. So post-Mauryan empires held to maxx 2-3% of Pakistani territory even in best of times
The Gupta empire ruled the Indus valley. Most of the Muslim kings from Delhi ruled Punjab. A few had Sind, Peshwar and Baluchistan under their rule.
One can argue the ruler of Punjab never ruled Baluchistan for most of history.
The fierce wars between the Durranis and Marathas in the 18th century in the wake of the Gurkani collapse was nothing but a reversion to this pre-Islamic delineation between Indus and rest of the subcontinent
The Marathas were driven away from Peshawar and rest of the Indus Area, but later in turn the Durranis had to retreat west of Sutlej.
The fact Marathas did not cross the Sutlej had nothing to do with Hindu-Muslim divide. Ranjit Singh the Sikh ruler went all the way upto Peshwar. Without Ranjit Singh there is a good chance Peshwar is under Afghan rule.