I thought the video was primarily talking about it for world building, which is why I mentioned Warhammer >_<. So please ignore that comment lol.
In terms of real life, presumably megastructures would suffer from the need to be built compartmentalised in order to avoid catastrophe from solar flares, a single stray asteroid or several & etc. But wouldn't that pave the way for power struggles? While it's true you can nuke your planet into oblivion, a planet is inherently more resilient to any kind of fallout from political turmoil. Whereas I feel like if somebody had a large enough power base on a megastructure you could essentially hold the whole thing hostage either through a workers strike or warfare which would prevent the structure from access to the required resources it needs in order to not collapse. Anyway like I said before, most of it went over my head so there's probably an extremely simple solution to the human element. Also you clearly know you your stuff so let me not pretend like I can
actually hold a conversation about anything to do with space. Thanks for the video, it was fun to think about.
P.S. Epictetus for best stoic