I took a look on librem. The only problem for me is called WhatsApp: without WhatsApp I'll be isolated from the rest of the world, and there's no fork.
Closed Source Fail. "Obtain your API credentials You will require api_id and api_hash to access the Telegram API servers. To learn how to obtain them click here....""
The point inside the open-source code where Telegram routes your connection into their centralized API, If you want true p2p Open Source cryptocomms see https://tox.chat/clients.html