“this is just going to go back and forth ...until there’s nothing left to put additional tariffs on. What’s the end game here?”
President Trump just announced that he won’t go back and forth - if there is another round, he will hit the Chinese 4 to 1. China can not withstand that.
China runs a net trade deficit with the rest of the world combined (they are very dependent on importing raw materials, oil and even food). The whole of their trade surplus, with which they build their military and bully their neighbors, can be accounted for by their exports to the USA.
The end game (if we are in it to win it) almost requires us to choke off China’s profits for National Security purposes, and to defend our allies. We can win a strategic competition against China much easier through trade than through military confrontation.
The first round of U.S. tariffs against China, worth $34 billion will go into effect on July 6. Steel and aluminum tariffs for the rest of the world will be going into effect soon as well, and the total of the rest of the world is to place new tariffs on a total of $75 billion of US exports. So the impacts of tariffs should start hitting next month.