You are the worst mama ever!….. You are the best mama ever…

Hello! Happy New Year!
So I have a feisty 7 year old, a 4 year old, and in the middle of a nasty divorce I never imagined.
The week with the girls went pretty well, but they were really resisting going for a walk in the afternoon on Sunday, and last Wed my oldest was yelling at me that I am so mean demanding her to do things all the time (like eat a banana so she doesn’t get hungry and put together a bag of toys if she wants to bring toys with her).
I can’t remember the horrible thing I did yesterday, but she ended up yelling at me, “You are the worst mama ever!” She has once said she wished she coudl jsut stay at her dad’s house, and once said she wished I were not her mom or something similar. Usually when she doesn’t to do something, like clean up, or put on a coat to go outside. She is very loud, at baseline, and more when she yells these things at me.
Yesterday, I thought I was going to crawl out of my skin for a few minutes, like I could not take it any more.
I know these are her thoughts in the moment = C, and that her thoughts also change and she will later tell me she was sorry she was angry that I’m the best mama. I dont need to be the best mama, but I do work my butt off at it, and am struggling right now – I’m trying to find the thought and the feeling I have at the time.
I feel like telling her…. Right, i’m a terrible mother. I do XYZ, etc for her. I have done and continue to do tons of things for her, signing her up for activities she likes, making special gifts, reading books, going on bike rides with her, singing her songs, loving her, teaching her things, showing interest in her, taking numerous parenting courses in order to help her more, occupational therapy, playdates, plenty of food, clothing, shelter, toys, etc
Any way, when she was yelling at me yesterday, I felt as if I skipped right to the action, of asking her if the worst mama does this for her and that for her and XYZ…, and at another point I jumped to the action of just walking away with feelings of despair, hopelessness, hurt, unappreciation.
I’m brainstorming a bunch of potential thoughts….
C: Daughter says, “You are the worst mama ever.”
T: I cant do this any more.
I have worked so hard to be a good mom, and she thinks I am terrible.
There is nothing I can do to satisfy her.
She is always dissatisfied.
She only sees what she doesn’t like and doesn’t appreciate all that happens that she does like.
All the effort I have put in doesn’t matter.
She doesn’t see all the things I do, she just sees the one time things don’t go her way
She is spoiled.
She is mean.
Why should I try anymore if she’s just going to not see it and attack me.
I’m exhausted of this – working so hard and getting attacked
I am not being seen.
She doesn’t appreciate anything I do for her
Fine, why don’t I just be the worst mama ever.
I am not the worst mama ever, and she thinks I am.
I should just let her live with her dad full time…. Then I have a follow up thought of how bad that would be for her and what a bad mom I am for thinking that.

I think all of these thoughts lead to feeling of hopelessness, helplessness, disappointment, inability to be effective, hurt, sadness, disconnection, anger.

As far as A:
There was one day I was able to tell her I loved her and be kind and loving in the midst of her verbal attacks, and we are usually able to resolve after some time, but in the moment I do not really want to be near her, have a hard time soothing her, and myself. I either walk away, or tell her fine, I’m the worst mama ever for suggesting she eat a banana before the car ride so she isn’t hungry or feel sick, or for taking her on a trip to hike near the bay.

R:
After some time for both of us we are able to re-connect, but I really don’t like being attacked by her. I have told her it is okay for her to be angry with me and to tell me, but it doesn’t feel good when she yells at me in such a way. She apologizes, and is kind for a while, until she gets to her rage place again.
I end up feeling on edge and on guard around her.

I’m thinking about the concept of boundaries. If someone who is an adult or peer, you can let them know that you are going to leave, take a break, not interact with them, etc. In this case, I really wanted to go for a walk for an hour, but I can’t leave a 4 year old and 7 year old at home alone, and anything I would do to give myself time (like putting them on the tablet for an hour) would be a reward for them.
I guess I have two things I’m needing:
1) Ladder or replacement thoughts in the moment… and probably in general for my daughter’s intense anger when not getting what she wants (??? Something like, this is just what she does when she doesn’t get what she wants, and that’s oka????)
2) How to manage boundaries with your young children, who are still too young to be left alone, and any way of getting space for me is a reward for them (for example I could ask the neighbor to watch them for 3 min, but then I’m afraid she will learn to just do that more to get to play more with the neighbor).

Thank you!!!