The pivot to China consisted of reassigning a couple of Atlantic based ships to the Pacific, then retiring more ships from both coasts while cutting military funding and promoting GOFOs based on their politics instead of their ability.
His administration was a joke militarily and left behind a shrunken, hollow force better trained on intersectionality inclusion and sexual harassment than on using their equipment properly. See the Fitzgerald and McCain collisions for proof, sailors driving multi billion dollar destroyers weren't properly trained to make course corrections and crashed into merchant ships.
Look up the Great Green Fleet, or his PACFLT admiral who said climate change was the US military's biggest challenge in the Pacific.
Look up Fiery Cross Reef or Mischief Reef, and what Obama did about them when China crossed that "red line."
He was a joke on China, a pathetic enabling joke.