The sovereignty of a country is also determined by its independence, which can be exercised without interference from other countries, including determining its own currency for the country's economy.So it is not easy to intervene in a country's sovereignty by changing or not recognizing its own currency, unless they are colonized and used as a source of war.but until now nothing has happened, and nothing has ever happened with that, other than perhaps providing flexibility for the use of US dollars, etc. to be accepted and used as a legal transaction.
What you say is not wrong at all because each country has its own sovereignty accompanied by complete independence as long as the country is not in a state of war. But it will be a different story if the country is facing war, so as long as the country is still safe enough, I think the country's leaders can still do something that can bring benefits to the country. As well as doing our best to rebuild its currency so that its citizens can experience proper progress like other citizens.