How do you do when grandmother is too attached

I'm starting to get frustrated. I asked my mom to help when he was a baby she said no that is your responsibility and she wouldn't even hold him when I had to take a shower etc. my mom has been overstepping her boundaries she often calls my son her son's name my brother's like she thinks shes getting a redo and I'm so frustrated when I was breastfeeding she told me he only love me because of my milk and that went too far she's always rude and has no manners she tells everyone it's her son that she's raising him when I'm home 24/7 I am the one raising him homeschooling him taught how to read, I potty trained him, I pay for the classes, I pay for the food, clothes anything and I'm frustrated not even to take a shit has she taken care of him watch him while I go to the bathroom no. Not even to go to the doctors office I take him with me. I'm sick of her telling him to call her mom and her telling her coworkers and church people that's my son even to me that's my son my baby I raised and I buy clothes for she buys one clothes on holidays birthday and Christmas I buy clothes shoes year round.

I need advice on how to break the reality that she doesn't have a redo her son is an adult and I am a woman, I am her daughter and I am a mother and I am raising a son.

She invited me to her friends house and her daughter had a baby and we were talking about grandma names and she said the baby will call her mom and the daughter looks at me and we're shocked and we go over names and the mom's friend she said oh what does your grandson call you and she said grandma and she said he should call you mom you raised him more than his mother and I'm right there and I'm thinking what has my mom been inventing and saying she does? Because I'm the one who gave birth who breastfed throughout the nights the one who had sleepless nights the one going to the doctor the one figure out allergies and making diet changes the one who potty trained the one steaming and pureeing vegetables the one who changed diapers and I could continue and I did it alone and I don't know what to say to people I don't know what to do.

I have some frustrations my family is complex my oldest brother cut ties with parents because they are toxic. My mom freaks out a lot and slams doors in your face when you want to have a conversation about your feelings and she gaslights says everything is your fault she doesn't admit she did anything wrong she will talk loud and say so everything is my fault like sarcastic or so we feel bad for her and have to explain everything again and it just ends up with arguments.