You've created a very dark and tense environment here! You definitely could put this in a boss fight and it would work. But it doesn't scare me, and I think it's because you have a very ordinary and predictable sound selection.
I appreciate that you didn't rely on cheap jumpscares via loud stings, but where are the freaky mangled sound effects? I want more than that metal thing people rub a bow on for horror noises. I want a super distorted scream in the background, scary footsteps, crying, dripping, horror_ambience_04.wav, ANYTHING. Play with the stereo field, make it sound like something's behind me. Or right next to me. Or just outside my room. Make me take my headphones off and look outside my window.
I also strongly feel that you neglected the low end. A really low rumbly bass that rises and falls in intensity is pretty good at giving me heart palpitations. Look into how composers like Hanz Zimmer incorporate bass into their sound. The TENET soundtrack is another good example of using low end bass in a cinematic setting. The low end here is just the low end from all of the instruments. I honestly can't tell if you did any EQ work or if this is all stock kontakt
A lot of people believe NG judges favor cinematic music, but imo any johnny with a cracked copy of kontakt and some libraries can make cinematic music. I went through a phase of that from like 2014-2016, and all it did was ruin my work ethic as a producer by giving me an unearned sense of accomplishment for work that I really hadn't done myself. (Heavyocity's DAMAGE, anyone?). I'm not saying it's wrong to use these tools, I just feel that when you do use them, you need to work twice as hard to make it uniquely "yours".
TLDR it's a good track, but there's no character to it; nothing to make it stand out besides being a cinematic horror song.