China isn't a free market, the government does strange things for reasons other than maximizing their own wealth. That completely screws over your analysis, companies go to where there is the most profits but undemocratic governments do not.
It is perfectly possible that China does this to weaken the US production industry making it more dependent on Chinese exports since it lets US buy Chinese goods with printed dollars instead of having to deliver anything in return. Then by suddenly ending this agreement it would devastate the US who is now unable to get those goods while China is left with the whole production pie.
> I don’t know how eurozone countries pay China
Europe exports to US and buy China, they are on average trade neutral since USA buys their stuff and they buy Chinese stuff. USA is the source of money and China is the source of goods.
China has yuan, Europe has Euro, why can’t they trade that? Clearly, they don’t want each other’s currency, and the best option for both appears to be USD.
(Assuming the premise is true, I don’t know how eurozone countries pay China).