Go Vietnam.
Say what you will, but they were the ones who got rid of Beijing’s Puppet, Pol Pot.
In 1979 when Vietnam invaded Cambodia (Kampuchea) and China attempted to invade Vietnam, we cold warriors called it a case of “dirty commies fighting rotten commies fighting evil commies”.
As for the millennia of bad blood between China & Vietnam, the Han Empire occupied Vietnam for a thousand years before the latter threw off the Chinese & later Mongol yoke. And it’s been nearly a thousand years since then.
Google “Tran Hung Dao”, a Vietnamese general of the thirteenth century who could give Patton & Rommel a run for their money.