El Salvador’s currency is USD such I hope we can agree is fiat. In 2021 they added Bitcoin as legal tender but that is not their primary currency.
Russia has “pegged “ the Ruble to gold. I do not think they have enough gold to back all circulating currency but it’s a good move on their part. The west (US) has sanctioned “Russian gold” so it sells on the black market at a discount to the price of gold, or so Kagi search engine tells me.
A good lesson in something that should be fungible made non-fungible.
I suspect we are on the same page, the world will be a better place when Bitcoin starts overtaking fiat currencies! But we have a long way to go!