An independent Khorosan is the solution. The establishment needs to change their policy, Afghanistan is too unreliable in the long-term, you can never have a pro-Pakistan government for too long. What if they are friendly until they build an economy and military then do the same thing as 1947?
Divide Afghanistan by giving Khorosan freedom incorporating Tajiks and Hazaras is the solution. Khorosan will have no enmity with Pakistan, and the smaller Afghanistan won't have as much potential to rival us at any point in time due to it's smaller size, population and land mass. It will be easily managed even if it is staunchly against Pakistan. Also they may begin to focus their chauvinism on the new border with Khorosan, so it will decrease attacks on us and we can have joint operations to control them. Khorosan may even be used as a medium to control that region.
To do this you must exploit the oppression and persecution Tajiks and Hazaras have faced historically, and ignite Khorosani nationalism or a fight to be free from oppressors.