this is implemented in a way that forces all existing messaging services to implement this or shut down

This is not possible. Anybody can host a messaging service as a tor onion, and there is nothing they can do about it :)

The only way they can make it work is to basically only allow connections to whitelisted services (not even GFW does that).

Zelensky will finally have to negotiate and end the war (that is, if he wouldn’t get overthrown/killed before that), and millions of Ukrainians will finally get to live without fear of them/their husbands/fathers/etc. getting kidnapped on the streets and being sent to army to die or get permanently wounded.