There should be a unified global response to sanctions. No people in or out (though their own citizens can go back but not come out again if they do), absolutely no tourism. No non-essential trade in or out (we don't need their plastic crap), with sky-high tariffs on essential trade to encourage divestment back to the West. All China-owned infrastructure and assets seized, with no further investments allowed. Massive tariffs placed on any country that continues to act like China isn't persona non grata.

The Great Wall(ing in) of China.