These key resellers (official, not grey market) often bundle Outlast 2 with other horror games for $5-$10 total. Humble Bundle also donates a portion to charity.
“SteamUnlocked is on the unsafe list. They have been caught wrapping miners and malware into their uploads. Don’t use them. Use [alternative site] or just buy the game on sale. Outlast 2 is literally $3 on Steam every two months. Is three dollars worth losing your entire PC?” outlast 2 steamunlocked