Off the top of my head, I can't think of anything that fits exactly, but if you're open towards extreme rule and gameplay changes, you could check out Soul Shaker by Lance Botelle. I haven't played it myself yet, but it's very ambitious, not typical fantasy fare, and heavily inspired by System Shock. You will have to survive in a total alien world. (Never mind the low rating on the new Vault page, there are only two votes and one is from a player who clearly prefers traditional fantasy modules and was not in the target audience; on the old IGN page it had much more votes and a much better rating - if you play it and end up enjoying it, leave a vote yourself!).

Revenant by McV might be worth a try for the dark mood as well.

I'm gonna try out both of those. I read the story description for Revenant yesterday when I was searching around, so I was intrigued, but seeing as you also recommending it has pushed it over the edge for me.

Btw you might know, when playing a module using EE, do you need to install the various "hack packs" that some modules require? Or has Beamdog already implemented them into the EE?

In the EE, there is a small curated selection of custom modules under the Community tab now, and if you decide to play one of those, the EE will download and install all required files in-game via NWSync

But for all the hundreds of other community modules (including Soul Shaker) you will still have to install everything manually. The hakpaks are often highly customized, especially for something like Soul Shaker, so there is no way around it.

There is however the Neverwinter Nights Mod Installer Tool (NIT) that's supposed to do all the work for you, if you just feed it the Vault page adress of the module in question. I have next to no experience with it myself as I guess I'm kind of a control freak and found setting up NIT more confusing than installing modules manually, but I'm a bit peculiar in that regard. I hear it's very good at what it does and appreciated by many NWN players. So if you don't want to install everything manually, give NIT a try!