This movie is really complex. I found on my first watch, I liked the first act and then it lost me. On a second watch, I was able to give the themes of the movie more thought because I wasn't being constantly blindsided.
This movie is about parenthood. Fear of being a parent, losing a child, losing a mother in the process. Grief over these losses turning people insane. There's also an argument to be made that it's about reincarnation, I'll admit there are still some elements I don't quite get. The people who felt tugged around by all the different elements are obviously not into Lovecraft, and that's understandable. It can be really dry and abstract. But cults, the cosmos, and grotesque creatures are all standard Lovecraft fare. Though it is rare that a story will use all three at once.
The worst thing about this movie, though, is that after deciding to spend the whole budget on some...rather stellar practical FX, they decided that the visuals weren't mysterious and cosmic enough to be considered "Lovecraftian." And how did they decide to fix that? Strobe lights, quick cuts, and shaky cam. The second act felt like going through a haunted house, which is really limited considering how much more freedom you have with film. I didn't fully see half of the monsters until I watched the bts reel. Lovecraftian horror is all about not comprehending what you're experiencing...NOT about being unable to see properly. Basically, they either should have proudly utilized their visuals, OR they should have done something more like Annihilation.