You should use SimpleX for private and safe communication between users and devices
It is extremely easy to set up - just install, pick a username, and pick your notification frequency
Unlike telegram / signal:
  • You can run on your own servers
  • You can compile the source code and use the resulting application
  • You do not have to rent a number from a mobile phone company
  • You are not linked between applications (eg the mobile number)
  • You are not linked between in-app conversations (NO USER IDENTIFIERS)
  • You are not being tracked (eg through metadata or MITM attacks)
SimpleX has voice / video calls, a desktop app, has very fast transfer capability for large files, is 100% open source, and now includes open channels for topic discussions.