I think building tension and atmosphere over gore is important. I kind of liken it to Stranger Things Part 1 vs. Part 2. I really liked both, but what really made the first one scary to me was how there was a lot of tension combined with the monster being shrouded in secrecy. As with many monsters, if you pull them into the light, they are still frightening, but less so in my opinion.
Another good example is Hitchcock's Psycho vs. the color remake. Because the original was in black and white, they needed to rely on something more than just blood and gore to make the story scary.
Personally, I think one the scariest films was No Country for Old Men. It wasn't a "horror," but they way they portrayed their villain was just...well I mean, I could see him existing in real life and that horrifying XD I realize those are film examples, but there are concepts that can be applied to comics 