@LovelyMMOG This is exactly my situation down to a T, and people who suggest things to say don't get it because it goes in one ear and out the other, they don't listen and even if they did, I think they can't help it, it's just who they are.
My mum isn't a bad person and not as extreme as the OP's mum, but still very draining. I also live far away from her and I've worked out that the golden rule is to keep our interactions to a 10 minute FaceTime call with only very superficial chat. Otherwise, It's constant low level criticism, disapproval and treating me like a foolish child. She also always has done that thing where she takes other people's side but never sticks up for me.
Some of my favourite gems of hers:
"Working shouldn't be at the expense of your child" (DD had recently started nursery and was ill a lot but I sent her in if she didn't have a temperature or stomach symptoms. Apparently I should've been keeping her home for 2 weeks every time she had a bug. She also wanted to know about every single symptom and constantly asked if she was getting better, every time she had so much as a sniffle. In the end I stopped telling her when DD is ill.)
"...and those things warrant that salary, do they?" When I explained my new duties in a job I'd recently started that paid much better than my old one. She knew how much being underpaid had affected my confidence and how hard I'd worked to get qualified for my new job.
"Don't feed your baby 'artificial milk', you need to try harder to breastfeed. Some women just can't be bothered to breastfeed." When she knew how much I'd been struggling with low supply.
"I thought you were a bigger size, well you're definitely not what you used to be", when I told her my size as she wanted to buy me a top for Christmas, not long post-baby.
She wonders why we're not close and I never tell her anything.