Radioactive Butthole

https://fedoraproject.org/atomic-desktops/silverblue/

Or for KDE:

https://fedoraproject.org/atomic-desktops/kinoite/

The konami code

Woah Briar is really cool. I think this is like what I want Signal to be.

Depending on how far you’re willing to push the definition of “messaging” you could look into getting your ham radio license. It can’t possibly be censored and allows you to communicate all over the world. You can even build your own radios if a government cracks down on them for some reason.