Honestly both are worth checking out if they interest you.
Kentucky Route Zero is an atmospheric "interactive novel" type of game, lots of complex branching dialogue that's well written and silent moments with the game's art and atmosphere, lots to dissect and it does strike a certain American Folklore meets David Lynch (in some ways) mood. Definitely not for everyone, but i've enjoyed it.
Outer Wilds is a game about discovery and exploring strange but interesting planets, with exploration, problem solving on the go and the way you progress is by gaining knowledge. It's also a game with some strong central themes that are told through gameplay and a balance of hope and loss. It's a bit hard to explain without spoiling the shit out of it, but it's a game best gone into as blind as possible and does have a lot going on for it in gameplay, though focused differently than most games.
But this is a bit apples and oranges here, honestly both have the potential to be stand-out experiences depending who you are. Just experiences very different to one another.