I think its' about time to go back to blackberry messaging days with person level invitations & complete P2P networking. Heck security by having every device be encrypted with a different scheme/similar
Keysharing parties? PGP-style, but with modern forward ratchet crypto?
Personal builds of the Signal apps that you share by installing them on your trusted friend's phones, and a backend you or a trusted friend host yourself on virtual servers outside Australian/FiveEyes jurisdiction?
(Give up and destroy all your electronic devices and only ever communicate with people you're in the same room as?)
I really like the idea of Bunnie Huang's Precursor, but its a fair way from retail availability still, and I doubt it'll be inexpensive enough to be able to convince enough friends to acquire one to make it any use socially.
I'm vaguely thinking of building a few devices with a TTGO TBeam and a Pi Zero, that can do medium range (1-10km-ish) LORA point to point and mesh networked shared-key encrypted comms to avoid touching the internet as much as possible, and that can provide (low data rate) mesh wifi bridges so other wifi devices can use the LORA mesh. Theres a project called Meshtastic that provides the bulk of that already on those TTGO boards, with a USB/serial/bluetooth API with some nice python example code. That'd still be "trusting" a bunch on non audible code on the TTGO and RasPi boards though.