Biden wanted to end the war as well but in a controlled fashion which the agreement precluded. The agreement itself was registered with the UN and there was no way to cancel it.
Was the UN going to force the U.S. out of Afghanistan if Biden re-wrote the agreement to his liking? The repercussions would have been a few countries making strong statements, if that.
Also a fracture in the world order with other agreements in doubt, US not considered an honest broker, ect.
There are centuries of evidence that the U.S. is not an honest broker (look at our treaty history with Native Americans). This would have made no difference.