"After US defeat in Afghanistan."
What defeat was that? We destroyed everything in the country that had any chance of threatening us with another attack like the one we were retaliating for, killed everyone in the country who mattered, killed anyone who had any objection to the former, left our enemy in ruins and crushed their families under our heel for twenty years. Now that we've demolished the country we're leaving its smoldering ruins behind and returning home while rats fight over the scraps we left.
And yeah, China's next on the plate, and the PLA is not going to put up nearly as much fight as the Taliban did. Having fought both I can tell you that from first-hand experience.