For those affected by the blocks, Signal recommends turning on its censorship circumvention feature.
Signal is being blocked in Venezuela and Russia. The app is a popular choice for encrypted messaging and people trying to avoid government censorship, and the blocks appear to be part of a crackdown on internal dissent in both countries.
Why aren’t they blocking telegram too? Is it because they use it a lot and can’t block it or because it is compromised, so they have access when needed?
They have not enabled the encryption by default and a common user can’t understand that. That is why it isn’t blocked.
Some say it was unblocked because they made a deal with Durov. Another opinion is that too many people and services including officials continued to rely on it even during the time it was blocked. Regardless, Telegram did a huge job on circumventing those blocks.
I think you are answering your question yourself. There’s nothing you cannot fully block, unless it uses vpns/proxies and then you can try and block those too.