The only thing I’m curious about is:
> Telegram stores all your contacts, groups, media, and every message you've ever sent or received *in plaintext* on their servers. [emphasis mine]
This implies they don’t use encryption “at rest” - unless I’ve missed something in their FAQ[0] (entirely possible, I’m far from an expert on cryptography), they seem to imply they do.
If it is indeed the case that they don’t encrypt data at rest, I can definitely see how that would be a problem.
If data is encrypted at rest though, I don’t see how any of that is fundamentally different from the other messengers I listed in the parent - the server still holds the keys, and thus must be a trusted party - but it’s nothing new.
[0] https://core.telegram.org/techfaq#q-how-does-server-client-e...