I don’t know about Russia, but I think if China decided to restrict capital from leaving their country, they would definitely crack down on crypto since escaping capital controls is crypto’s primary use case and China knows that.

You might ask “what does such a crackdown look like?” And the answer is, they would simply round up and throw in jail prominent crypto people, make it a crime to do anything with crypto (buy, sell, use as currency etc.) and put the fear of god in everyone else so that nobody dares touch crypto.