China Russia paranoia at this point is unfounded, China won't expand territorially into Russia, Chinese population will stablize at around 2025, and then start to massively decrease by 2050.
With advances in tech, less and less lands are needed, farming and manufacturing will move to African and other developing nations as we become developed.
Our population will be about 900 million by 2100. About 500 million less than 2025 numbers.
So at least for foreseeable futures no conflict, at least in terms of land.
As to Vietnam and India, if they want we can sell them weapons to use against us if they want. The all mighty dollar is just that all mighty.