It ends with I need to be patient and respect her boundaries.
When she (or x) says this, I wonder what she imagines you, your DH and DS are doing in the meanwhile? All sitting around, life on pause, stressed, waiting for her?
The rant will be very influenced by x and x's politics even if it isn't written by her (but possibly is). And you don't deserve that. You're entitled to get a little bit cross at being emotionally manipulated yourself, at the barrage of ranting whipping you into submission. Really, you're a normal loving mum, a decent ordinary family, this melodramatic teenage self-indulgence can go too far.
I'm thinking of my young DS who can push my buttons like no one else until my nerves are at breaking point. I take it and take it, but there is a point where my voice gets very low, very stern, and I firmly say, "I have had ENOUGH!". And he stops. Instantly. Eyes wide, cautious about what he says next. He knows what he's doing. He doesn't hear that voice often, but when he does, he knows he has overstepped the mark.
Figure out where your boundaries are and how much further you're willing to go and be tormented. And then be ready for the moment that your DD needs the tough lesson that, equally, she needs to respect YOUR boundaries - psychological, emotional etc. You are not her punching bag. It must be so awful for you walking on eggshells the whole time.
I suspect that if you hadn't mentioned DS, the fact you invited her at all would have triggered something. They're embroiled in fighting with you.
Let the rope go slack and let them find another punching bag.
❤️