Dollarization has been done before under Menem where essentially the peso was backed by the US dollar. I don't know exactly how milei plans to do it or how much power he will have to do it. My guess will be that his presidency will be similar to Trumps. He will be dealing with a lot of protests and pushback from the bureaucracies while at the same time becoming more moderate with his proposals. He is already starting to walk back on some things he said he will do.