i played Subway Midnight recently and enjoyed it a lot. it does have a couple of jumpscares, but it’s mostly weird, creative VFX and atmosphere. gameplay-wise it’s essentially a walking sim. it’s on Steam and maybe also Itch.
a kind of obscure horror-ish (but really only ‘ish’) rpg-ish game that i really love is Fragile ~さようなら月の廃墟~ (for the Wii). i think you mentioned studying Japanese elsewhere, and i’d recommend playing it in Japanese if possible (no idea if there’s a ROM, though, and the Wii is region-locked, and also you’d need a Wii).
Siren: Blood Curse is a great game which iirc doesn’t really use jumpscares (been a long time though). it’s the most classically horror-like out of all of these (zombies and weird rituals). the overall atmosphere is very well-done and creepy. this one is on PS3; not sure if it was ever released for PC.
totally second the person recommending Kitty Horrorshow.
(also i’m recommending lesser-known things here on the assumption that recs like Silent Hill would be too obvious, but if you haven’t played, like, Silent Hill 2 or the Fatal Frame series, i think those would fit the bill for mystery, plot, vibes, etc.)