I do feel for you OP, but moving out and going NC is the only way to save your sanity. How she is, is not your fault. And she is not your responsibility.
I know someone who has gone NC with his mother around a year ago. He is 25. (I will call him Josh.) His mother was manipulative and controlling and possessive, but was also vile to him, and criticised him daily. Yet Josh is the loveliest, sweetest young man in the world, and she was damn lucky to have him.
He has a brother who is a year younger who is mommy's favourite. Their dad (who never married her,) left her 12 years ago, when the boys were in their very early teens, for another woman, and married her within a year. She never got over it and never a day went by when she didn't rant about 'that whore.' She was always a cow before, but was worse after he left. Unsurprisingly, she has never had another man since.
Josh met a young lady in very early 2015, and after a year of dating, they decided (at the age of 24,) they would start looking for a place together. They kept it to themselves whilst they looked.
Long story short, when his mother found out, she went utterly mental and threw him out onto the street. He had to go stay with his girlfriend and her parents for a month until they got somewhere together.
His mother told him never to come home and to get his father to come get his stuff. He did. The sad thing was that there was hardly anything, and only a shoebox full of stuff from his childhood and no toys or anything. She threw everything away. She has no sentiment, no feelings, no real love for him.
A year on, and he hasn't spoke to her since, he has had his birthday, and her birthday, and Christmas and New year, and has not flinched once. He has stayed NC. Everyone who knows him says they have never seen him so happy and chilled. He was constantly worried about being whacked across the head, or screamed at, or criticised, and was never allowed in the lounge (in case he messed it up,)....... And now nothing, just a life with his lovely girlfriend, dad and stepmom, and 2 step sisters, and his girlfriend's wonderful family.
The relationship with his brother broke down though as he sided with the mother. However, no-one else in the family did, as none of them can stand her either. Even Josh's nan (his mother's mother,) chose him over her! His mom said to the nan 'if you speak to him, don't speak to me again.' Fine said nan...And they haven't spoken for a year either. In addition, Josh's 3 cousins still have contact with him (the mom's brother's children,) because they can't stand Josh's mom either....... and their dad is close to Josh too. (His mother's brother.) Apparently, he isn't keen on her either. So she literally just has the younger brother!
So yeah, go NC, you will be better in the long run. A toxic mother is soul destroying.