No, however a character directly threats/implies intention to do so. Even though it doesn’t get to that point, it could be quite distressing because it seems like it actually is gonna happen for most of the scene so I’d say be careful.
Yes, a main character is crushed under rubble of a ruined building with a friend of hers who passes from his injuries, she survives, but it’s implied not everyone in the building did
Yes, five unnamed teenagers are found having suffocated in a cargo crate, and later several more kids are murdered in the same crate the first five died in
Yes, not frequent, but it’s very explicit when it comes up (some vague spoilers ahead)
The entirety of chapter 61 is from the point of view of a character during their unwinding, who is unable to feel any pain but is conscious and aware the whole procedure up until it is no longer possible. It is quite disturbing, not a much gore is described, but it’s pretty clear what’s happening to him as it happens.
Teenagers are shipped in crates in an airplane cargo hold, four in each. It is mentioned later that five of them who had to share one crate due to lack of space died during the journey
It's complicated but if this is a trigger, I'd advise you to avoid this book. The premise is that after a war over reproductive rights the agreement was that all pregnant people must give birth but they can have the kid "unwound" (killed) when they get older. This is presented as something that would satisfy both pro life and pro choice and that really annoyed me as this is literally the opposite of the pro choice ideology. Also, there is some "both sides are bad" rhetoric.