Coriolanus
Crazy how the more one thinks about a realistic depiction of FTL space travel (& communication),
the more it contrasts with existing scifi fiction-verses that involve it... ~^<-<^~
For instance; if the means of FTL travel is via metric tensor manipulation, like an "Alcubierre Drive", than the civilization that managed to create such a machine could just as well weaponize it directly.
~i.e.; "metric shielding" for blocking passing interstellar medium ([spoiler]or incoming physical projectiles[/spoiler]), "spacetime catapults" ([spoiler]like railguns, but with spacetime manipulation rather than electromagnetism[/spoiler]), "metric shells" and "jackets" for containing, compressing, transporting, and projecting/releasing the blasts of nuclear explosions, or even ""*PP-wave spacetimes*"(pp-wave spacetime)":https://en.wikipedia.org/wiki/Pp-wave_spacetime of death. ([spoiler]spacetime-tearing naked singularity beams that delete everything in their path, created by collapsing spinning metric bubbles & aimed by pointing their axis of rotation.[/spoiler])~