If we fix our politics and our economy, we will be largest business opportunity for Afghans. Secure the border fence and ask the Chinese to pressure the afghans to cut out their crap in exchange for the trans-Afghan railway, in which everyone benefits. Work with our citizens in the border areas to provide job opportunities, making goods and providing services needed in Afghanistan. Cutting smuggling so these products and services must be sourced from our citizens at border markets. Tying the future rebuilding and sustainability of Afghanistan to Pakistan is the only way to make it in their interests not to challenge the border, because if they do those border markets in those sectors can be closed.
This can be a two way street. Afghanistan’s current rulers can use this an opportunity to reshape relations with Pakistan for themselves and their people. The Afghans don’t want foreign forces in the region and a resumption of the last two decades of war. They also can’t be seen to lose face in front many of their ethno-nationalist countrymen. Furthermore, they need the means to sustain their economy as well as run the country largely the way they want to, in accordance with their culture.
They need to make it in Pakistan’s economic interest to prevent foreign intervention into their country (such as a value added processing industry to their mining sector), and offset any financial benefit Pakistan may get by accommodating extra-regional interests. In doing so, they can claim they are protecting Afghanistan through diplomacy, and can use it to reign in militant groups on their side of the border.
They can also negotiate more free access for Afghan citizens to officially (instead of de-facto) move freely in Pakistan and make the border a line of administration, but not a significant barrier to free movement of people or goods. Afghans already move freely into Pakistan, why not use this as an opportunity to shape that relationship that extracts benefits for Pakistan, such as no movement of arms, taxing goods moving across the border, and skills development of Afghans so they have viable livelihoods to go back to. A stable Afghanistan with Pakistan’s help could also add more weight to Pakistani relationships with Central Asia, and a Russia (once they end the war in Ukraine and need to rebuild via regional partners)
A more prosperous Pakistan would not be at the expense of Afghanistan and a prosperous Afghanistan would then not be a threat to Pakistan. A peaceful region would attract FDI and a rebuilding Afghanistan (financed by mining profits) could be a growth engine for Pakistani consumer market and value added industries like food processing, mining processing, and shipping at Karachi and Gwadar port.