Good messaging apps: Signal (requires phone number), Session(based on Signal protocol) https://getsession.org, Wickr, and some others. Remember, Telegram is centralized, with poor security, Matrix is federated (you need trusted server or self-hosted server to use it without fear of be nuked by server admin), Parler is questionable (centralized, needs phone numbers etc), so it wasn't good choice from the start. For decentralized networks study this: https://en.wikipedia.org/wiki/Peer-to-peer Messaging apps comparison(not all good apps on that list): https://en.wikipedia.org/wiki/Comparison_of_cross-platform_instant_messaging_clients#cite_note-wire-servers-13