Leaders like him lack the clarity to lead. This issue is not about "Pashtun tahaffuz". It is about a foreign power destabilizing Pakistan and some parties leaning on that to push their domestic agenda. The less said the better about this.
Let's also be clear that in general no Pashtun wants Pakistan's FATA/KP to be absorbed by the Takfiris sitting in Kabul no matter the ethnic linkages.
The rationale on the other side first - The reason this Takfiri Emirate of Afghanistan (TEA) is hurtling down the path of conflict with Pakistan knowing it stands very little chance in a head-on confrontation is because violence, destabilization is conducive to their goal of an ideological, takfiri take-over of Pakistan along with Afghanistan. They have not thought through what it will take for this to become reality but ongoing "Takifiri fassad" is their means to this end. So not matter what Pakistan offers, TEA will never abandon the destabilization efforts against Pakistan and TTP is their instrument.
PTI may think that it can operate in this conflict from the sidelines (which is what it has done thus far by sticking to basic non-polemics to avoid any strong anti-Taliban positions) and letting the center duke it out with the TTP/Afghanistan. The violence in KP will increase manifold in the coming period. Their own ppl will start questioning the PTI leadership for its lack of resolve in this fight. Recent reporting suggests a lot of the funding for TEA/TTP is coming from poppy cultivation inside of FATA. These sources need to be cut off and urgency needs to be applied to the requests to Qatar/KSA to completely cut off Taliban from all foreign funding and any/all international support. Except India, there are no other takers of Taliban on the Int'l stage and Pakistan needs to push this narrative hard.
Overall, Pakistan's choices are limited and of varying costs but whichever side has the stronger resolve will win this out (and keep in mind that Taliban's choices are even more limited). If Pakistan resolves to hit Afghan and TTP kinetically and otherwise in Kabul and elsewhere, then it will need to be a sustained campaign taking the fight inside of Afghanistan instead of letting Pakistani mainland be the battlefield. Turkish experiences with Kurds in Syria could be used as example. Each attack should result in significant damage inside of Kabul/Kandahar and also include periodic takeover of bordering Afghan posts and potentially areas well inside their borders for indefinite timeframe so the staging ground for Taliban/TTP gets pushed further away from KP/Tribal areas.
It goes without saying that Pakistan will need to stir up the ethnic fault-lines in Afghanistan. Economically, Pakistan needs to tighten all trade to Afghanistan and just do the bare minimum as the UN expects for landlocked nations.
If there is a behavioral change seen on the part of TEA, tactics need to be relaxed to offer carrots. Indians will try to play spoilers but if there is continued covert/overt support, Pakistan has to activate options in IIOK and potentially even in the Indian Punjab, Sikkim etc. to raise the costs for Indian machinations. However, the first order of the day is to put military and economic pressure on the Afghan Taliban. This can be done but needs a strong resolve and not one that get's disturbed by nonsensical domestic politics.