I don't think "blocking relays" will work. A threat of 10 years in jail if they got caught connecting to nostr relays would do the trick. We don't have a tech problem. We have a people are hypnotized by the state for tens of thousands of years of problem.
But that goes to my final point. Imagine in the future if normies used all sorts of apps that tie into Nostr. Like it just becomes normal, because the interoperability makes them better apps over time. It becomes very hard for a government like Brazil to ban something like that. Imagine countless popular apps and websites across multiple categories going dark at once.
Mullvad VPN. Tails OS. Orbot.
The idea that if something gets popular enough governments won't ban it hasn't really worked in the past. They ban anything that's a threat to special interest. Wasn't cannabis plant leagel world wide at one point? Wasn't in used in EVERYTHING?
But it’s not just one thing in that scenario. It’s a Gordian knot of a bunch of things using some particular communication protocol among many other communications protocols. Government bans work best on the public when they have one clear thing to propagandize. Like “cannabis is really really bad!” or “Musk isn’t above the law, so we will ban X until he complies to prevent disinformation!” It’s much harder to play perpetual whack-a-mole with a bunch of different things. The propaganda narrative becomes diffused and unclear, the cost to enforce goes up, people might not even know what underlying technologies different apps use, etc.