Oil is being smuggled through Iran. The number is probably 10-20% of the total oil imports. The state is not getting any tax receipts from such smuggling activities.
Secondly, from what I understand is, now Pakistan is not selling oil below the global spot rate. They’re actually charging dubious levies and taxes on oil prices.
Thirdly, you can gradually increase oil prices if need be, but the rate of acceleration in the last year is unprecedented.
Forthly, currency devaluation translates into steep oil prices in Rs.
The state has many avenues to tax the undocumented economy. Real estate, agriculture, digitizing the economy, reduce smuggling etc. But as we all know, it won’t happen.