Recommend me some slow and really gloomy repetitve post-punk songs like Joy Division's Day of the Lords or Interpol's Pioneer of the Falls. Something that's dark and moody and guitar based but without getting too heavy.

Tunnel Vision's "Watching The Hydroplanes" should fit the bill here. Slow, despondent post punk from a band who were contemporaries and label mates with Joy Division.
https://youtu.be/OCY_TAYFYzw

And if may indulge in some blatant self-promotion, you may like some of the slower material from my band Jesus Fix: heavy goth/punk with a bit of metal in the mix.

https://jesusfix.bandcamp.com/track/wai ... he-silence
https://jesusfix.bandcamp.com/track/bring-me-god

Atriarch is a doom band with a lot of post-punk sensibilities.

https://www.metal-archives.com/bands/At ... 3540333368

Not a trace of metal to be found in my rec, but Ritual Howls have some remarkable funerary sides:
https://ritualhowls.bandcamp.com/album/into-the-water

You should check out the new Gnod album "Chapel Perilous".

Perfect example: https://youtu.be/kuqEOyRu90s

I didn't know this demo. They sound a bit more polished now. But on the whole, they are one of the very few modern coldwave bands that don't sound like a rehashed take on Joy Division, Siouxie and the Banshees or you name it....

Here are two bands you should certainly check out. The first one is named Lebanon Hanover. They have some incredible morbid guitar and bass work mixed in with dark and cold synths, and the vocalists sound so detached. I just got into them a couple months ago and they are incredible compared to other similar bands imo. The second band I HIGHLY recommend is Kaelan Mikla. 3 piece all girl band from Iceland. It would be their self titled album that would have the kind of style that you might like. I also recently got into them and this album is one of those ones where there is literally no bad song and the album seems to go by very quickly. All the songs are slightly different, especially in the vocal delivery.

Here's a couple links:

Lebanon Hanover

https://www.youtube.com/watch?v=WPw7nlluRdc

https://www.youtube.com/watch?v=ES0QyLZZ9EQ (The intro guitar and basswork completely blew me away when I first heard it. Literally a more fitting little riff could not have been written haha)

Kaelan Mikla

https://www.youtube.com/watch?v=dIB4WUa6Py8

https://www.youtube.com/watch?v=-cHiQLVSdo4 (This song I honestly get vibes of Burzum)

Hope you like them!

I am actually making something in this vein now. Full electronic, though.