The appeal of souls games as I see it is the Mystery, not the horror or whatever.
A player runs through looting and feeling accomplished because of their incredible skill at beating the strong enemies. This becomes LitRPG, in novel terms.
A players runs through, talking to every NPC, reading item descriptions, exploring scenery... Because they're curious. They want to know what everything means, if it has meaning, and if there's no meaning, why is it there at all? It's a Mystery, and there just happen to be horror elements as a spice.
So... To recreate that 'feeling' in a novel, you'd need three things.
A protagonist who experiences a cathartic flavor of growth over time, either through stats or character development. Defeat this obstacle that stumped you for four chapters, encounter new obstacle.
A mysterious and deep world, where the readers have plenty of opportunities to guess what's happening in the background, but these details are never explicitly stated except as a reward for the MC's growth from rule 1.
And Some random dark, horror, or dysmorphia to wig out the readers, mixed with bright sparks of humanity and courage. There's a reason the most remembered characters from the games are heroes and companions like Solaire and Onion Knight: They're the thing that readers can cling to in the darkness.