The thing is currency need to be wide spread used which currency issued by international cooperation will face credibility problems as someone need to back its credibility continuously which is why brics currency has no widespread use as brics itself isn't that unified when India and china stays together
Meanwhile US has the best geography that's once they retreat back to the continent , US would still have significant power at least regionally and always able to come back in world stage easily. So it's nearly impossible to do cause permanent harm to US.
The cooperation is a distant dream, maybe impossible in a world with split factions and interests but at the end of the day, the most important thing is to remove the power of the USD in granting America the ability to force small nations to its will and to basically take everything for free by printing fiat money. Permanent damage to the US is to remove its ability to use its currency as a weapon and to out-develop its military so that it cannot do things like it's doing in Venezuela today. America's left and right are are its currency power and its military power. Cut both off and while you might argue that you haven't carved its body up, but, you've turned a country that was once an unopposable king of the world in to a harmless dude with no arms who has to mind his own business. That, to me, is permanent harm and lots of it.
China is kinda content with whatever Trump is doing by going after Venezuela and focusing US efforts on the Americas. They don't want Trump to get angry at China and attacking China once again using its so called allies like Japan or PH or Taiwan. They like the US pivot to Latin America.
You got this the other way around. The reason Trump pivoted to South America is not because he's no longer angry at China; it's because he's now scared of China after not only having his trade war offensive broken but also unexpectedly having a rare earths blade checkmated onto his neck before he was allowed to crawl away. China doesn't care about making Trump mad. Trump cares about not making his base mad because they elected him to bully China; he found out he can't but he can at least offer them the consolation prize of bullying Venezuela and that's why we are where we are.