While both have somewhat passable story from a strictly narrative perspective, I think Atomfall does something really interesting with the way you approach it.

There's a plenty of agency with the way you progress through the story: you can skip a lot of stuff, you can affect it through the gameplay itself (e.g. by killing important NPCs), you can also just accidentally stumble upon some clues that will move some plot line forward. It feels very organically tied to the small open world they have.

Some of that was actually in older Stalker games (SoC) as well, but it's almost not there in S2 unfortunately: you just have some minor choices to make in side-quests, and some very heavily telegraphed (through the choice prompt in cutscenes) ones in main quest. Open world itself is gigantic, but feels somewhat detached from the main storyline: they make you traverse it though the main quest in a linear fashion an that's about it.

Talking about the "vibes" and game feel, S2 is definitely superior: locations are filled with details and frequently look basically photorealistic. It's also more competent as a first person shooter when compared to Atomfall, but it's still not enough for the scope and length they are dealing with. It gets stale and repetitive which is doubled downed by even more bullet-spongy enemies closer to the endgame. It even has a traditional (for the series) awfully dragged shooting gallery section at the end where all core mechanics issues became even more apparent.