Living Between the Stars
In Isaac Arthur's latest video at the time of this posting he focused on civilizations that may choose to live far from any nearby stars for whatever reason. Most likely stationed on rotating habitats or possibly rogue planet-like bodies that aren't in orbit around any star.
Since such colonies would be far away from any nearby stars solar energy would be impractical. Exotic sources of power such as from dark matter or dark energy might be possible but with current physics the most likely source of energy would be nuclear fusion for lighting and heating the habitat.
The analogy of living in a log cabin on top of a hill and occasionally driving to town was used. An exo-stellar civilization would scavange molecular clouds for raw material and fuel. Depending on how much power could be generated fusion could possibly be used to create heavier elements that aren't abundant. one-way communication with a neighboring star system might take weeks or months.
It could seem lonely but the video also refers back to previous videos on the possibility of uploading minds and living a digital existance. If I had to live between star systems that would be the best way to do it.