Yeah, I thought Bidens timetable was by early Sept (before 20th anniversary of 9/11) but troop withdrawal was accelerated. Googled and found articles confirming it
US forces to withdraw from Afghanistan before Biden’s deadline
Interesting article in New York Times (from May)
American troops are set to be out by early to mid-July, well ahead of President Biden’s Sept. 11 deadline, even as big issues remain unresolved.
www.google.co.uk
Basically they continued with the accelerated withdrawal even though Taliban was advancing and breaching terms of the Trump agreement (probably not a surprise to anyone !). Ultimately, looking at the way it’s panned out, it probably hasn’t made a huge difference is as soon as US and allies withdrew, the taliban taking over would've happened but optically, the scrambling to get people out could’ve been managed better.
The bigger and far more complex question is once in, whether they/we should’ve continued to stay at some level....potentially for years more. If so, why.