I’d dial down the labels like narcissistic, poison etc. Even if you aren’t saying them within earshot of your child they’ll be conditioning your own state of mind. Which can leak through. It’s not helpful to grow up thinking you are at least half “awful person”.
As terrible as you are feeling, right now the situation needs a clear head and well managed emotions. Big feelings leading the path forward doesn’t always end well.
The one thing that always stood out to me, as the child in middle of it, was how parents go on about how they’d jump in front of a bus to save their kid, and mean it.
But then be entirely unaware that their Big Feelings were the actual kid squishing bus.
I have more sympathy than you can immagine. I don’t think anything could hurt me more than my child at risk of alienation tactics. Failing to rise to provocation, making your home a safe, secure, non-volatile, free from emotional bombs place that kiddo can retreat to, is your safest path to navigate your child through a potentially future altering landscape.
When you next give them a massive hug, add an extra squeeze from me. We need fewer newcomers to our tribe, not yet more.