Boyfriend’s mother (50+yo) despises me (23yo)

As the title clearly says, my boyfriend’s mother cannot stand me.
The reasons as to why she doesn’t:
– I have social anxiety and I didn’t want to call someone on the phone when she practically tried to force me to. ( had a long talk with my boyfriend after this where she told him I’m good for nothing and I won’t help him in life with anything )
– I didn’t go straight to her after coming in the house to salute her. ( my feet were hurting and I wanted to sit down first for a bit )
– I have ‘problems’ because I have coloring books and I color in them as a hobby to destress.
– I apparently influenced her son to be disrespectful towards her. ( because she isn’t first priority in his life anymore & doesn’t keep up as much )
– I am a vegetarian. ( because I don’t eat whatever she cooks and she feels disrespected by it )
Now, I also don’t like his mother. She is very passive agressive and acts innocent after insulting you, is not satisfied with anything I do, speaks harshly to my boyfriend and is very clearly upset her son, as good as she made him to be, isn’t only hers anymore and is upset by it.
I didn’t want to try to be close with her ever since I saw how mean she could be with her own son ( ex. she yelled at him for moving a plant from his own room, asked if I made him do it & told him to not arrange things in her house ) but I tried to have a somewhat ok relationship with her. I have brought her a gift and flowers for her birthday, listened to her talk for hours. That was one of my attempts at staying civil, but she only continued to make subtle remarks about me having ‘problems’ and talking about his ex. ( she says he never acted this way towards her when she was with his ex, that she was respectful and they always came in her room first to salute, always ate together ) To this, my boyfriend told me his ex was basically a doormat and let his mom do as she pleases. Even if she would tell her she is dumb, she wouldn’t say anything.
Last night, we finally had a big fight as you’d call it and she says I influenced her son to not speak as much to her anymore and that I changed him to not be her ‘child’. Mind you, he is 23 years old. He told her he is trying to have a future together with me and is, indeed, focusing more on me and that this is a talk they already had. She says we are only boyFRIEND and girlFRIEND, not married and that it’s not his time yet anyway, so he is still her child and should act as such. That I have taught him to be disrespectful as I am. After saying my own point of view about things, I tried to tell her we should have limits for my boyfriend, because this situation stresses him out too and she mockingly said I am no therapist and that her son isn’t stressed. In the end, she left after saying she made up her mind about me and that he didn’t find anything special, that I’ll cheat on him, etc etc.
So, about my boyfriend. My boyfriend will come live with me and my family for the holidays since she no longer wants him (or me) to stay in his house. He also doesn’t wanna break up and instead wanna get our own place after he gets some things settled so we’ll no longer have to deal with her.

What can I do to resolve this situation or at least make it kinder on my boyfriend? He is extremely stressed by being torn between us two and by other factors so, I don’t wanna add to it.

tl;dr: boyfriend’s mother completely hates me and thinks I changed her son and taught him to be disrespectful towards her. don’t know how to make it kinder on my boyfriend after big fight.