You have two conditions: not dense enough or too dense and the fractal nature of population mean you can have both. Radio bandwidth is a precious resource and if you think somehow that anything good will come out of sending a packet N times you are not likely to manage a wireless network successfully.

There are systems like

https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_Sys...

But they are pretty specialized and not that scalable

Agree! And we need also to consider that a mesh protocol for Meshtatic/Meshcore should support mobility and have to run in a low power devices

Any promising mesh networks, radio networks or routing protocols worth looking into?