Welcome to the forum Frustrated!
And yes... I'd say being frustrated is most likely an euphemism at this point, I was personally, and still sometimes feel completely enraged !

But then again, we only have power on ourselves. I cannot change my mother, she cannot even change herself. Radical acceptance is the only thing that truly made sense for me, and from that point on, I was able to see, more clearly, where my power truly lies and to act accordingly.
I found I can choose not to stay in contact with my mother, and I went no contact. Truthfully, I don't like my mother and don't enjoy her company. And I realized I do not have to like her... She was not a mother to me, not in the sense that matters anyway.
Fighting her (and myself to have a relationship with her) was useless and resulted in a loss of energy and deep ruminating. Cutting contact gave me space to heal and observe myself. Now... I am a month of official no contact in, and 6 months of very low contact to no contact (non-official), and I feel better... I am slowly regaining my sanity and power. There was anger, there was depression, but now, I find there is more and more serenity and acceptance of it all.
Are you still in contact with your mother?
What advice appeared juvenile to you? I am curious of what you tried, but found not helpful?