Trying to navigate relationships with a mother who is always negative.

OP is human too and can make a choice not to further put up with this from her mother. This is not a mere case of her mother getting it wrong; she does this because she can and it works for her. She is behaving appallingly here and such behaviour is normal for an abusive relationship. Her mother will not want to address her own issues and instead of seeking the necessary help is likely repeating what was done to her.

OP - Its not your fault your mother is like this and you did not make her that way. I would urge you to back away and further lower all contact levels. Do seek counselling from somewhere like BACP and find someone you can work with and someone at that who has no familial bias about keeping families together despite mistreatment. I would read further about codependency and see if any of this applies to you in relation to your mother. You do not mention your dad here; where is he?. You may also want to look at and post on the current "well we took you to Stately Homes" thread.

Do you think that your mum sees the world this way (i.e. a puddleglum) or that it is something she does with just you?

If it is just towards you then she may have evolved a habit of being negative towards you which could be addressed together.

You will get a lot of 'your mum is abusive, you should cut contact' here, but your mum is human and we all get things wrong and develop bad behaviours. In short, we are none of us the sum of a Mumsnet post.

It’s not normal.

Or rather it’s normal for an abusive relationship.

My mother made me feel special and loved and never denigrated.
And I’m doing (or hoping I am!) the same with my daughter.

I agree with everything CalmDown said. It's not an unusual problem with mothers, but its certainly not something you have to accept. As you say, its incredibly exhausting and tiresome.

How often do you see her? Can you reduce it, and keep visits/ calls brief? I would certainly cut down on the amount of information you share with her. You say you dont want to call her out on it, and that's very wise, because shes highly unlikely to change. I second the idea of counselling for yourself, to help unravel the impact of her constant criticism on you

It's not normal, no. Unless you can imagine having a conversation and asking her to address it (and I get that this seems unlikely) you can really only reduce the amount of information you give her. The less she knows, the less she can put you down.

I would encourage counselling to help you understand how this has impacted you over the years.