Actually, at 144 levels, thermal control is relatively easy. Because below 5-10 feet or so, the ground temperature is actually relatively constant for a the next several thousand feet (we know the Silo is around 144 levels, at 10 feet per level (which is under estimating the height of each floor) that's only 1440 feet, or under a quarter mile). This is important because this is what geothermal heating and cooling systems work at - they rely on the ground being relatively consistently around 10C/50F in temperature. (Geothermal systems are also called "ground source heatpumps" - your traditional heatpump/AC being "air source heatpumps"). Though, with the silos so close to each other, it's possible that each one influences each other (It's hard to get the scale).
So the silos would have a reasonable source of constant temperature soil around them. And generally speaking, once you condense that many people together, the heat of all that activity inside will probably raise the temperature quite a bit. It's why malls like the Mall of America don't actually have the ability to heat the building - they constantly run the AC on all year even in the winter. Otherwise the mall would overheat from all the activity inside (though, in winter they probably intake fresh air than actually run the AC to save energy costs since it's already so cold outside).
In general, the cold air is piped to IT, where all the servers heat it up and that warm air is used to warm the silo. Or supposed to be, I presume there are ways to move the heat around.
Of course, the bigger problem is water - I don't know what the water table is like near (spoiler!) Atlanta, GA, but I suspect it's higher so there is a need to pump out water. And also to remove it from the air - that many humans plus plants would make the Silo a really humid place in short order. Especially Silo 17 which should've been completely rusted over.
As for the darkness - I suspect it's more of a TV thing. Most 4K TVs simply cannot display HDR properly. And most people are buying the Black Friday TV specials which are basically garbage at HDR. Sure, they claim to do it, but most computer monitors supporting HDR only do "DIsplayHDR 400", which is marketing speak as it's still basically SDR. Which is probably why those of us watching at 1080p are fine, as are anyone with a higher end setup (OLED and the like). Even though HDR has been around for over a decade, it was only really post-pandemic where the display technology started being able to show it properly - older high end 4K TVs still had issues with HDR, and most of the Black Friday special range are really HDR in marketing speak only.
