Personally, I'm partial to a slow burn horror movies. I don't mind jumpscares if they serve a purpose other than to startle you. For example in Hereditary, one of the jump scares is the mom driving alone in her car and she hears her dead daughter make her signature mouth click sound. That startles you, but also lets you know the daughter may not be gone. As opposed to a generic jumpscare like a cat jumping out of a window with a dramatic music sting.

My all-time favorite horror movie technique is a lingering camera after the dialogue and characters leave. Like even if they don't show anything it makes me uneasy. I don't know what that's called but it's so good if the director does it right.