May I suggest you try “Keet” by holepunch. A decentralized messaging app.
WhatsApp may become illegal in UK - and messages could be seen by authorities, warns boss
https://www.mirror.co.uk/tech/whatsapp-become-illegal-uk-under-29442761
Discussion
Keet is not that secure...
Oh, I wasn’t aware. What about Telegram ?
A little bit better... but still centralized.
Keet creators assume that every user is behind a VPN, which in fact, some people don't know what a VPN is, and if they know, they use a free one (which I don't recommend), because you don't know where your data is going, and most free VPNs have a killswitch.
We have developed an app that is heavily encrypted, and uses the LN Network to send messages, it's still on alpha version, but you can take a look at it. Feel free to give us + or - feedback. https://play.google.com/store/apps/details?id=com.blipmeapp.app&pli=1
If you would like to check the source, feel free to do it: https://github.com/BlipMeApp