I am so with you.
What helped in my case finally, was that I used same weapon my mom was using against me.
I've send her letter where I simply and honestly described what I think of her as a person and her life choices.
I was NOT trying to be harsh or mean, I just wrote down what I was thinking about her.
She got offended by it and that was it. She never contacted me again.
Because in her mind it was my job to come to her and apologize for my disrespect.
Job well done!
I knew I'd be feeling bad about it (hurting mother's feelings), but I've been "inappropriate" son already!
Feeling guilty and insufficient after every interaction with her.
How can it go worse?
So I felt about it like ripping off bad tooth, causing you constant pain, but just just below the level that will force to go to the clinic - as you are scared of more intense but short pain doctor will cause you, you are rather accepting lower but constant pain as part of your life.
I knew I'd feel really bad about how horrible son I am to my mother (which is nonsense, of course, because I was just about to be honest same way she was honesty with me),
but in long term I got rid of pain from constant nagging and judging and whatnot, which was really poisoning my life.
I must admit I felt cornered - it was like me or her.
So this is my experience.
It happened more than 6 years ago.
I didn't know FDR and RTR back then - nowadays I'd try RTR approach first.
Hope this makes sense (I am not English native speaker)
Best wishes, Jan