The world pre WWI was as globalised as we are now.
The yanks and Chinese will be at each others throats within out lifetimes.
Sadly, this COULD be avoided.
The US is uniquely positioned to be energy AND food independent, a very rare capability for most countries and none of the other current world major players can claim the same. The US is also in a great defensive position with oceans on almost all sides (if we kinda fold in Canada) and a southern border that could be closed quickly with any desire to do so.
We could then just kinda sit out China, India, Russia, and Europe deciding who controls what and very quickly the unequal distribution of food and energy would lead to a lot of countries collapsing and mass famine. It may still happen even if the US stays as World Police (TM) but the only real reason the US and China would fight is Chinas desire for regional control (much like Russia in Ukraine) and whether or not the US wants to deny it. China is FUCKED if they can't sort out some serious internal issues with their population.
They are expected to go from this:
to this in just 16 years
That will CRUSH them internally unless they get to having the babies and/or allow MASSIVE immigration, and who is rushing to go to CHINA?
The US and the West can avoid this situation by selective immigration of "the productive ones" and then try to culturally indoctrinate them as much as possible to preserve the local customs and language but I don't think China can do that.