"I got this game a while back through the large 2020 bundle, and I was wondering if I’d be able to put it onto Steam for some of the useful metrics like playtime and stuff..."
Ah, sorry about that. If you go back and read the details on that bundle, it specifically mentions that it doesn't include Steam keys for games which otherwise have 'em. You can always add the game to steam via the little bottom-left UI, "+ Add A Game" -> "Add a Non-Steam Game..." Would that work for you?