Outer Wilds is hands down one of my favorite games of the last decade, and one of its major strengths is forcing the player to make peace with mortality in a way that is neither weepy nor explicitly frightening. The universe ends, and you are part of the universe. Simple as.
But for dealing with such an inhetently human concept as facing our own mortality, the game's story is pretty emotionally sterile. There's no complicated interpersonal relationships to deal with, no moral dilemmas to struggle through, no real attachment to the characters you know are doomed to die every 22 minutes.
This is a common limitation of a lot of existential Western sci-fi. It's partly why Lem wrote Solaris: to try and inject humanity into a genre that seemed to consider humans tangential while exploring the Big Questions of life, the universe and everything.
I don't have any real point to make here I just like using hexbear as a diary to jot down my shower thoughts that can also give me feedback on said shower thoughts
On the other hand, the game also says that you aren't insignificant, that you don't truly end at your death, that you will ripple into eternity through the effects you have on other people and the world. The nomai all carried on these grand projects over the course of multiple generations, the other travelers might have sort of given up traveling but the player is the culmination of the space program and everything it's learned, both of these collide as you discover and continue the work of the nomai. And in the end all of that adds up to everything being able to live on.