Matches come from the tags Steam players vote on each game, weighted so a rare tag counts for far more than one that sits on half the store. A game's popularity never moves it up this list.
The closest matches to The Cost Of Bliss on Steam are Those Who Remain, Inside the Backrooms, The Exit 8, Gravewood High, Shipwrecked 64. They rank highest because their Steam community tags overlap most with The Cost Of Bliss's, and shared tags include Psychological, Stealth, Choices Matter.
How are games like The Cost Of Bliss chosen?
Every game is described by the tags Steam players vote on it. Rare, specific tags such as Psychological, Stealth, Choices Matter count far more than catch-all ones like "Indie" or "Singleplayer", and each game is scored on how closely its whole tag profile matches The Cost Of Bliss's. Popularity never affects the ranking.