Wouldn't multiple central banks (each with their own currency) be the best? Or is that what you mean? Then people can choose which currency (and thus which central bank) seems the most stable and legitimate (as long as it can also exchange with the currency they pay their rent and taxes in).

(Theorizing about cryptocurrency is fun as long as you ignore how actually-existing crypto, like actually-existing communism, is working out in the real world. Although that doesn't mean all the underlying principles are wrong...)