Let us start at the beginning. This problem is nothing to do with what you are and everything to do with what your daughter is.
Speak to your other children, they, I am sure, will tell you, have already told you, that none of what this difficult daughter says about you is true. Everything she says comes from within her and is her exercising the power she realises she has to diminish you and make you, a professional women doubt yourself.
So the first thing you need to do is to stop taking this offensive talk as personal to you. Ignore it, do not respond to it. Find a mantra or short phrase to repeat to yourself aagain and again ,when she starts ranting so that you can curl up in its comfort. It may be something like 'I am a successful professional woman' repeated again and aagain
The second thing you must do is start to put some clear water between your daughter and yourself. You say your grandchildren have ND problems, but apart PDA give no indication what these problems are. We are a ND family, but how it affects every family is immensely different depending on the problem and age of the children.
Stop going to the house in the morning and helping the children get dressed and out to school. It might be beneficial to all of them if they did have to manage without help. It may mean that they start being late to school and having problems that do attract, or make necessary, school or social services intervention.
Thirdly make clear to your daughter that unless the abuse stops you will offer no help at all. tell her, if she starts abusing you, you will walk out of the house immediately and leave her to manage on her own - and do not return for the rest of the day.so. She will eventually get the message.
jenpax the solution to this problem is in your hands, but it needs you to take action, and if necessary leave your daughter to manage alone with her children. I cannot think that that result will be any worse than the current situation with a harridan of an abusive daughter shouting at you and the children witnessing it all.
Finally get counselling, there is nothing you cannot tell a counsellor and she will help you recover your self worth and stand up to this difficult daughter
Also turn to your other children, they may not be near you but phones and zooms and texts and whats app, can all help you keep in daily touch and if they know that you are dealling with this difficult situation, I am sure they will give you all the support you need