[Pharmakon]

Of course if we’re talking about an FTL-capable civilization then our understanding of physics is out of the window to begin with. I don’t think it’s reasonable to expect a civilization with FTL to make Dyson spheres or swarms, and it may be thst even if FTL is impossible it could be I desirable to build them. If the need to hide distinct technosignatures for some reason (Dark Forest perhaps) then any civilization would avoid Dyson structures.

[ben_w]

FTL makes it worse. The only tech we need for us to Dyson up (95%?) of our entire visible light cone is self-replicating factories that work in a vacuum on (for example) Mercury: http://ukspace2015.co.uk/presentations/36

FTL makes that 100%, from beyond out cosmic horizons, even if it turns out that FTL isn’t automatically also a time machine like we currently think it is.

Pocket universes might help? I don’t know though, I’m saying that only because I’ve not seen them ruled out.