Depends on what you want. If you want Signal-like security and everything it offers on avoiding collecting data that it can view/analyze, then I'm guessing noth

Depends on what you want. If you want Signal-like security and everything it offers on avoiding collecting data that it can view/analyze, then I'm guessing nothing. Maybe Matrix (matrix.org) with E2E is close enough. Wire (wire.com) is another one that has better features than Signal and also has E2E for all conversations.