I must recommend Thronehammer. The band is about to release it sophomore and they're imo among the very best modern epic doom bands. Their debut made a strong impression on me, went though completely under most radars.

This new song is the testimony of they ever growing talent:

https://youtu.be/veiqWA9wqCQ

I just had to check out a band with the name Thronehammer, couldn't help myself. Not bad but they should ditch the death vocals. Don't see any point in having them when you've got a perfectly good clean singer.
Having completely different styles of vocals is pointless, unless they're portraying different characters or emotions which I didn't hear in this song.

What if it's the same dude doing both styles? Singers like to show off what they can do, y'know. Part of the art.

Yeah sometimes it works and sometimes it doesn't. In this case I don't think it does and his clean vocal suited the music better. The needs of the song should come first artistically, not the singers need to show they can do everything just because they can.
Paradise Lost is an example where they usually make it work nicely.

Depends on the listener, I guess. I'm always happy to hear singers do their thing to the fullest of their abilities. We have so many albums out there with completely one-dimensional vocals... why berate the guy for trying harder

Yep depends on the listener. I'm just another armchair critic with an opinion and you know the old saying about opinions. Tho I hardly think I was berating him.

Please recommend me some songs/albums/bands, of any subgenre, that have a very "scary" atmosphere and give a feeling of impending doom, like these:

Black Tomb - Church On The Hill: https://blacktomb.bandcamp.com/track/church-on-the-hill
Sunn o))) & Boris - Etna: https://sunn.bandcamp.com/track/etna-2
Atramentus - Stygian: https://listen.20buckspin.com/album/stygian

Atramentus has to be linked to the "school" of funerary extreme doom initiated by Evoken which are mandatory (less the two latest albums of theirs), then try Indesinence, Tyranny by any means, Anhedonist...

Black Tomb, it's some typical misantropic Sludge. Check out Toadliquor, Ramesses, Khanate, Grief for similar stuff. There're plenty of them. Noothgrush's 'Erode the Person' too is a classic. Some among the most crushing bands in the style are Halo, Buried at Sea (their Migration album is super heavy), Corrupted (verging on Funeral doom), Volition...

edit: I skipped the "scary" part of the request as it is really very personal and every thing slow, dark and crushing brings a smile on my face, but if I had to point you to one specific doom project, I'd say Tyranny.