https://www.state.gov/wp-content/uploads/2020/02/Agreement-For-Bringing-Peace-to-Afghanistan-02.29.20.pdf

Which part says the US would bje abandoning equipment? And in particular, which part days they would be abandoning military equipment if the Taliban and Al Qaeda broke the agreement before military forces were removed?

How do you defend yourself until the last person leaves if you start taking home all your equipment?

You evacuate civilians first. Then equipment and personnel in a balance between number of personnel left and the amount of equipment they can use. You have an understanding like Trump had, that if the afghanis attacked US citizens or military at any stage during the withdrawal, the US would unleash a series of bomb strikes on the culprits’ installations and homes. Why would Alqaeda invite that response from Trump during the withdrawal, when with a little patience they could make their play to take over the country once the US were extricated.

But they didn’t have to deal with Trump. They had grand dad, little old poll-watcher Joe.