Not applicable to Telegram, but if the app is open source and you have a Mac (!) you can install it using Xcode.
Since Signal is actually open source, you can install it even if Apple decides to block it in the future (if you have a Mac).
Since Signal is actually open source, you can install it even if Apple decides to block it in the future (if you have a Mac).
So technical users could install for their friends.
You can reinstall it every 7 days for free though!