Actually switching to crypto and resulting lower demand for national currency would be part of the problem increasing inflation.
I don't see why its true. In fact, the opposite seems to be more or less obvious if you insert "new" and "old" correspondingly.
russia and north korea saw that making western companies (some of which can pay up more than entire government budget in some of these countries) transfer rub or whatever is not working for many reasons (eg. if banks allowed it it would implicate the government etc). So their ransomware gangs use crypto now.
Russian ruble exists in name only. Well, it is used in country as normal for now, but it's nearly illegal to buy foreign currency in useful amounts so official exchange rate means nothing.
In truth if you want to actually help Russians/NKoreans, cutting money supply/laundering mechanisms for the elites would be a big step in that direction and crypto is a big big part of that now.