I've always been interested in helping folks that help folks.
I started looking at Meshtastic, some years ago, but found the ecosystem to be a bit overly-complex, as is often the case, with "Swiss Army Knife" approaches.
It is true that you will not be able to jam the _downlink_ frequency outside local areas.
But due to the FM capture effect, anyone else in the same hemisphere with a basic 100w transmitter (and appropriate antenna) on the _uplink_ frequency will be able to deny the satellite service to all the 5W Baofeng radios that preppers are stockpiling.
Look: if someone is jamming something with a 100 watt transmitter which causes impact on the adversary, that location is quickly bombed because it is now a giant beacon that advertises its position.
I'll even throw a cheap appeal to authority and mention that I've done this stuff professionally in the military for a decade. I'll still trust more on the usability of my cheap walkie-talkie capable of +50km range and satellite texts than an exotic LoRa used on the ground by few internet warriors.
In a real scenario these things work. Please don't fall into "what if's" which are exotic and confused as things bigger than what they are.