At the moment I’m trying to convince my wife to use Delta Chat instead of Whatsapp.
Unfourtunately there are some issues that are difficult to excuse:
It is expected, that all or at least the last message is shown on the locking screen. Especially when several messages are send from the same person. See Whatsapp behaviour.
At the moment only the first message is shown on the locking screen. All further messages are supressed and can only be found when opening the app.