When a child/teen blames their mom for all their problems

Hi, I think it’s called being a kid/teen during/post Covid. My 14-year-old 8th-grader would like to lay in her bed all weekend and after school watching Netflix and YouTube. Plus some texting and calls…add to that a new opposition to healthy food and all her old favorites and refusing to do her chores and a hair-trigger defensive reaction to anything I say. And yes, nothing right now is her fault and I’m (mom) to blame for everything.

For me it’s lonely and exasperating and infuriating. I have firm screen time rules that she complains about endlessly. I just keep hoping for other interests to kick in. Sometimes I think we ALL are depressed with life’s pressures for perfection and throw in bad air quality, fires and the threat of power outages, the recall election and many other crazy things. 
Sending patience and please take care of yourself. 

Sounds like you are having a really hard time with this issue. I totally understand because kids have so many distractions such as video games, Netflix, and social media and we want to see them being productive and active. I actually don't have an answer for you and I am not a psychologist. I don't know it is a "named" syndrome, but there are predictable dynamics at work here. I know that communication can break down between parents and kids. Have you evaluated the quality of the communication you use to explain your feelings about their behavior? While it was over 40 years ago when I left home, I was very angry with my parents and blamed them for a lot of my issues because they were always telling me how to live my life and their love for me seem so conditional on whether I would be the person they wanted me to be. They just could not listen to me or let me figure out what was right for me. Certainly, kids under 13 need a lot of direction, but by the time they are teens, they want to know they have more autonomy in how to run their lives. With my own teen/young adult kids, I have realized the only thing I can do is to work on my communication with them. I have working on using active or reflective listening skills. A good author to check out is Thomas Gordon who wrote "Parent Effectiveness Training". 

I think it’s a desperate move to get you to change your mind, and to hurt you. I think it’s very common — so common that it doesn’t have a name. 
My son often used it, and I weathered it because I felt confident about the decision I had made. 

I thing they call this condition "adolescence".  >.<
I feel your pain! Unfortunately, I think it's a completely "normal" albeit very unpleasant behavior/ part of their psychological process.

Hey, this could be me you are talking about (the kid's Mom who is blamed for everything)! The situation bites and I feel I can't win. I'm blamed for 'ruining' their life, when most of the time, our only real problems stem from us just trying to get them offline and into the mix of our life and family. My child is 15.

Maybe the child is angry at mom.  In which case, therapy for child, or therapy for mom, or both, might help.  If a kid is angry, they can blame mom for everything (from personal experience).  And maybe a trip to the pediatrician to make sure there is not a medical problem.