You seem like a rather superficial (black’n’white) thinker; but this is a complex situation with many moving parts. Trump is a shades-of-meaning negotiator, and he was well aware that they would soon violate the agreement, in which case he could renegotiate the terms, or justify a massive bombardment. A lot depended on whether he would have received a mandate, which he did, discounting the election fraud.
Apparently people seem to believe that Trump's plan was to beat the Taliban to the punch, violate the agreement first, and continue to leave U.S. troops in Afghanistan. I find that hard to believe. He was too set against continuing the war there.