What was the USSR after in Afganistan??? Dirt, Mountains??
Strategic pipeline access between the Black Sea and Indian Ocean. Afghanistan has always had a strategic position in the region, even if it is just dirt.
Irrespective of what you think/thought of president George H. W. Bush, he said during the campaign he lost for reelection that the world was actually in a somewhat more delicate state after the collapse of the USSR, and that it was a crucial time for the right leadership. The country wasn't listening, and we got Clinton. So much of what we're dealing with now is a consequence of what happened during the 90s.
I believe they thought they could take out Pakistan or Iran afterwards - piggy backing down to a warm water port.
I think they wanted access to a warm sea port?
I take it that you are not familiar with Kiplings Kim. All about the 'Great Game' of Britain against Russia in Afghanistan, preventing Russia from getting access to the Indian Ocean?
Access to Iran and it's oil, plus a possible war water port. Afghanistan was just a step. Turned out to be a doozy.