You are being set up to fail - that is her MO.
Your Mother has chosen to do and say the things she has for her own reasons. It's not YOU that caused any of this and the only change you can effect is to STOP her doing it to you or your DC going forward.
this bit is the hard bit, but please know that it will get better.
When we escape our abusers it's not a destination reached, it's a journey started. Mostly that abuse started WAY before our abusive partners showed up on the scene.
when you have poisonous people in your life, this is what happens. they dent you as a child, and that places you at greater risk of falling prey to others of their ilk. You are drawn to the familiar, and the familiar is not good.
You have to think of yourself now, and your DC. Protect those she would harm because she wants to feel the power it gives her to do so.
Its jealousy, resentment, fucked up. But you don't have to allow it in your life. it's seen as a taboo to dump your parents, but it's not a decision any one has ever taken lightly, and if ever there is a whiff of 'oh but she's your mother...' tell them to walk a mile in your shoes and then come crying to you.
I wonder often who I would have been had I had the support and love of my parents as opposed to criticism and resentment. I never thought my mother was so set against my happiness. But now I see that she was. :( SUre there were many times that she showed it, but i'd been conditioned into thinking that what she did/said was normal. only when my Ex left and friends asked if my family were supporting me and I told them they had all fucked off to the other side of the world (again, planned all year, but only communicated to me on Christmas day, 8 weeks before D day, which they knew full well)
It's the pain of the realisation that we got them so wrong that hurts. i remember feeling utterly and completely idiotic for days after my loathsome ex left, but that was a skip in the park in comparison to the day I realised that, yes, she really WAS going to keep her address all to herself. I didn't ask her for it. I let her do what she wanted to do, I left her the rope to make her own noose.
Now is the time for you to sit back and observe her unravel as she realises she has lost her victim. it will be unsettling, but you have to let her go. as you did your ex. they are AS bad for you as one another. They are one and the same.