As far as being scary, neither Evil Within game was scary to me, but I don't really care about that.
The horror part in this RE4 style of Action Horror game that I really appreciate comes in the form of enemy design and overall game design. You wouldn't have shit like the ghost sidequest and how it affects your game if it wasn't a horror themed game. The limited resources part also makes basic combat decisions a lot of fun.
So I don't really think too much about which one is more scary, because I don't really care.
The reason why I love the enemy and boss design in the first game isn't because it scares me, it's because it's creative, looks great, has memorable silhouettes and the fights are a blast, even with one hit kill mechanics.
You wouldn't get the crazy kind of enemy design and variety you find in Action RE without the horror themes, you just need to look at basically every other TPS around. The Last of Us has the best enemy variety in any of the modern Naughty Dog games, and it also has its horror influences. Horror is simply an endless source of awesome enemies, so every game like this benefits from those themes, no matter how scary it is.
Not that I don't appreciate games that are actually scary, but when they go too far in just trying to scare you like in the recent wave of Amnesia-inspired horror games, the moment they fail to do so, there's not much of an interesting game left. It's why I really dislike Outlast. It didn't scare me, so it was just a slog. Nothing in RE4~6 comes close to being scary, but I'm still having the time of my life playing these games because they're fantastic. Stunning folks and then kicking the shit out of them never gets old, hiding in lockers and waiting certainly does.