I wouldn't count satellite as a viable option for citizens during a war, especially if it's under US/foreign control (a possible enemy).

Meshtastic seems to be very vulnerable to misconfigurations that can knock out all nodes in an area by flooding them. All it needs is 2 nodes with MQTT enabled and nobody can communicate.

Jack Dorsey has alpha software and just rewrote another app. Plus, he's from the USA so his stuff shouldn't be trusted. Briar and other apps already exist. Maybe even Jami could work. The problem is that those are only the range of WiFi or Bluetooth. For communication in a city/town/village,that might be OK, but intercity communication won't be possible. Is there no meshnet tech that has greater range than WiFi and can carry more than text (I.e not meshtastic)?

There are really two categories to "war resistance". Did this war completely knock out the internet? Then your limited to satalite, meshtastic, physical radio tech.Maybe jack dorseys bitchat would work since everyone will already have the hardware to build the network out.

If you have internet...then Tor, I2P, and other overlay networks will remain very resilant and allow you to communicate over any distance...that's what it was made for.

Severing fiber connections between Sweden and central Europe won't matter to Tor. It's whole job is to make secret unblockable tunnels.

Any type of distributed service, really. There are many, and there are tiers of service as well. Meshtastic is probably going to be the most useful in the Lora arena, since anything can be a repeater.