All civilizations basically have a "Civilization Broadcast", which is a Special Tool.
Only the civilization leader can use it.
It can send a broadcast deep into the universe, but in most cases, these civilization broadcasts are not received by other civilizations, as the propagation speed of the civilization broadcast is equivalent to the speed of light.
The range is a radius of a hundred thousand light-years; it doesn't dissipate before reaching the end.
And it cannot be destroyed.
To reach the end, it needs to propagate for a hundred thousand years, a very long distance. On the Star System Map, it seems like there are many civilizations here, but in fact, each civilization is very far from each other.
Almost 99% of the cosmic broadcasts drift like cosmic souls in the universe and have never been received by anyone.
