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.