There are many dead dogs toward the end of the movie, at night & already dead in the woods. You don’t hear anything but see them already dead with blood all over. There is also a dead dog at the bottom on the stairs in Junko’s ancestral home.
There are dead pigeons around during the film and one seen of a man grabbing a pigeon and walking inside with it. You don’t see what happens to the bird. There are about 4 pigeons who fly into a window and are shown dead after.
[Spoilers]
While not outright pedophilia, some material may be disturbing to CSA survivors and especially disturbing for cult survivors - particularly Kana's story. Kana is a psychic child used as the temple for a supernatural entity, and fed aborted fetuses to establish a connection with the entity. The latter incident is never shown on-screen.
Her ghost is later seen with the ghosts of the aborted fetuses; it's not made clear what exactly is going on, but one interpretation might be that she was forced to give birth to these babies (albeit by supernatural means).
There is also a lot of themes around Kana 'being devoured' or eaten by parasites; while the context is more literal, it can be taken as a metaphor for sexual assault.
the woman does not walk out of view after setting her sleeve on fire as mentioned in another comment. as the rest of her body catches fire, she begins to scream and try to escape her predicament, while her husband desperately tries to help her. this scene could be triggering for anyone who is upset by burning alive
Multiple instances of parents losing their children occur throughout the movie. The final scene shows a man's wife burning to death, as well as losing his adoptive son.
It’s mentioned that people committed suicide by hanging in a park but it’s not shown on screen. There’s also a body shown after committing suicide by hanging.
There are a couple of scenes with people eating and clinking cutlery. In general, since this is a a found footage movie, there is a lot of background noise and scuffling in different scenes which may bother some people.
The character Hori seems to be panicking or having an anxiety attack in many scenes he is in. Hyperventilating, becoming erratic, screaming, fidgeting.
Not directly confirmed, but there are implications. Most notable with Hori, who appears to have trauma-induced psychosis (though this is also a side effect of coming into contact with an eldritch abomination).
-SPOILERS-
Abortion is mentioned because there are ghost aborted fetuses, but it's not looked down upon because they were abortions. The only negative thing implied is that they were illegal late-term abortions done by the clinic Junko worked at.