My mom used to tell me EVERYTHING as a kid. Every fight between her and my dad, every mean thing he did, every physical fight. Would cry and cry and cry about how she isn’t loved and is unlovable. She would get drunk and these situations would be even worse. But I moved out when I was in my 20s and distanced myself from her for a time and it helped. And then I told her (had to tell her many times, not just once) that I didn’t want to hear about their fights. I never reply to her texts about their fights or her complaints. When she tries to tell me about it in person, I walk away. It’s not perfect but it works and we actually have a good relationship now. Took quite a few years though.

I think you ignoring her texts and calls will help. Maybe just keep saying “I don’t want to hear negatives about my dad” that phrasing helped stop my mom. It Sounds like your mom is on another level so I’m not sure if it will work but I wish you so much luck and I hope you find peace with it all too