Check:
https://SecureMessagingApps.com
rate
🟩=3
🟨=1
🟥=0
Result
86 Threema = 86 Security Points = most secure Messenger
81 SimpleX Chat
80 Signal
77 Session
68 Wire
61 Wickr (Amazon)
56 Element / Matrix
37 Apple iMessage
32 WhatsApp
27 Telegram
26 Facebook Messenger
10 Microsoft Skype