Russia is already blocked from ChatGPT and Bing; I don't know about China.
But it's all security theater. Plenty of people use it with VPNs, and I know several who found it useful / interesting enough to bother paying for it (which involves foreign credit cards etc so it's kind of a hassle). I'm sure so does the Russian govt.
In any case, I don't see how you could realistically block any of that without effectively walling off the rest of the Internet.