There are other more plausible options for these civilizations then building absolutely gigantic structures around suns. 1. Build devices/objects (https://i.yt

There are other more plausible options for these civilizations then building absolutely gigantic structures around suns. 1. Build devices/objects (https://i.ytimg.com/vi/bQ7RaOMHb5I/maxresdefault.jpg https://i.ytimg.com/vi/bQ7RaOMHb5I/maxresdefault.jpg) that are able to get close to the stars, that would then absorb the emitted energy from the various coronal ejections, magnetic fluxes, etc. 2. There is more energy in the fabric of empty space-time than anywhere else. An advanced civilization would likely be able to harvest this ZPE (zero point energy or field) using rather small devices.