Terrific review. I definitely think you make some valid points. Although for me, the identity crisis you describe elevated the movie more than hurt it. His later films suffer a bit more in that regard I'd say. I think the discordant element of family drama Aster added in really heightened the sense of unease. It makes many other horror characters feel a little flat and one-dimensional by comparison. I don't think you're supposed to entirely like the characters as people. I certainly didn't.
That was an interesting point you made about god feeling absent from the movie! I felt as though that wasn't a problem in the slightest. That woudn't have even occurred to me as an issue truthfully. Religion isn't a very powerful presence in most of my all-time favorite horrors. In movies like the Exorcist I think the overt presence of religion comes off as gratuitous and actually cheapens the real sense of horror for me.
I've been hearing a lot of great things about the Babadook recently! I've been meaning to give that one a revisit. It didn't have an extremely lasting impression on my first watch through for some reason.
Thanks for reading and publishing, Simon!