Is this scarier than Babadook/Conjuring/Insidious?

Not necessarily scarier.
But I'd argue it's got more variety, which makes it stand out as a great movie.
It's got it all: at times it's relentlessly intense, but at the same time you have these slow depressing scenes.
They manage to combine really dark drama with brooding spooky vibes, weird shit, psychological horror, genuine scares, and more.

Conjuring and Babadook were not as varied, much more focused in their own niches (Conjuring being a straight forward haunting where you know the supernatural stuff is gonna be 100% real and Babadook being a stylized, intimate drama combined with horror)

It depends what you find scarier ... jump scares or mood-building.

Hereditary builds a mood, like The Babadook, that culminates in some scary scenes.

The Conjuring and Insidious are mostly jump scares.