I really think influencer culture ruined the reaction to this movie. It was an experimental indy movie last year, and everyone that saw it under that reputation was like "wow, they made a lot work with no budget." But then people got crazy about it with the "this is the scariest thing I've ever witnessed in my life! It's Hereditary on steroids, bath salts, and crack!"
Now people are going in with expectations through the roof, and bound to be disappointed.
I think it was pretty effective. There's tropes, but they're used well and I like how much you backstory you can figure out without having it explicitly explained to you. But it had 1/6th the budget of Sinister, and one location to shoot. It's flawed.
If you want to see a horror movie that genuinely sucks, Psycho Killer just came out. That's a dumpster fire. Undertone is a cool gimmick on a decent movie, and the ritual stuff gives it a nice edge (though, I still put Incantation ahead of everything that's tried the immersive approach).
