Unless those urls are unique per user, then the response to that is for the blocker (Russia in this case) to install the app and block the URLs as they change
(You are right about not requiring completely unique urls per user by the way).
This is a nation state suppressing information, I don't see why wholesale blocking services like cloudflare or any of the other possible options would be a non-starter, given it only needs to last for a weekend. There also doesn't appear to be any evidence that this app uses any of these techniques either as far as ive sedn.