It's FOSS - https://itsfoss.com/cutegram-linux/
Brief: Cutegram is an unofficial Telegram client for desktop Linux. It provides more features than the official Telegram client itself.
Telegram is one of the best instant messengers for Linux and it definitely needs no introduction. It is loved by the community because you can install Telegram in Linux thanks to the official native Linux client. Telegram runs on my Android phone and on my Linux desktop, so life is good.
Telegram is also privacy-focused, featuring a combination of 256-bit symmetric AES encryption, 2048-bit RSA encryption, Diffie–Hellman secure key exchange.
But the thing that sets Telegram apart is its limitless