The first game that came to mind after reading your post is Subnautica, such a great game!
I’m going to recommend 3 smaller games that I found to be very atmospheric.
The Invincible: A scifi walking simulator based on an iconic novel. The music and the graphics suck you in and the voice acting helps keeping you interested. I recently replayed it and loved it again.
Gris: A small platformer on the easier side with beautiful hand-drawn graphics and (IMO) great music. It tells a sad story without words, so good.
Oxenfree: A scifi thriller in the form of a side-scrolling platformer. I played it years ago so I don’t remember much of it (my memory is crap like that) but I know it left a very good impression, especially its atmosphere.
Honorable mention to Valheim, which I see mentioned in the thread ore than once. Great atmosphere and gameplay loop, although for me it lost some of its charm in the later biomes they released afterwards.
I hope you find any of these to your liking.




Let me know what you think of them if you end up playing them, I’m always curious to read what others think of games I love.