As long as they don't try to pretend it's all peachy keen...
IE, 12 worlds have been destroyed and billions are dead as society lies in ruins -- but we survivors are going to stop for a fun jaunt at a casino planet!
Give the characters and audience something hopeful to hang on to and you can at least go ankle-deep into the gritty side of the pool rather than trying to gloss over such a critical element.
Give them a real reason to survive, to hope, to go on.
Star Wars had a rebellion, Terminator (originally) had stopping Judgment day, blah blah... example example, lol.