Bluetooth and wifi messengers have been awful over the years, but pretty much every hardware messanger (Gotenna, beartooth, and now meshtastic/meshcore/TTN/lora etc) have been very effective.

Also FRS radios are still a thing.

Though it still would be nice for cell phones to be telecommunicators instead of *cell* communicators.

Meshtastic works great up to two hops.

FRS radios are bulky; Meshtastic is the way. It's really made for this type of event.