Plus remember, one common "feature" between all nation-states' currencies that have international trading relationships with the United States is their reliance on the U.S. market for the strength of their own currencies, which then makes them vulnerable to the pressure from the U.S.
Well, the real strength of a fiat currency comes from the economy of that country in addition to their resources, political stability, and basically what "backs" their fiat. USD was strong because it was backed by oil (Petrodollar, a scam US regime ran for years). CNY is strong because of the massive size of the production based economy of China. and so on.
Not to mention that these days many countries are moving toward accumulating gold and back their fiat with gold (which is one of the reasons why gold has been soaring over the past couple of years).