yeah my son is the only grandson until this one comes along, she has 6 granddaughters so he is like the flaming chosen one lol I am the same I want my mum to enjoy it but as a grandma, I have the exact argument with my partner about his mum. He has a daughter from a prev relationship and due to his shifts his mum pretty much raised his daughter, but now I am here she is so off with me all the time and is obsessed with his daughter to the point that he is terrified of saying anything to her, and now I don't really want her to have anything to do with our son!!
The problem you have from what you say (and am sorry you were paid off cause of ill health I hope you are ok now), is that it sounds like your parents 'did you a favour' to give you a job, but you just have to sometimes stop and say look, I love you but this is my family, my kids, my baby, I want to spend time with them, bond with them, as I should being the mum and as your parents you would hope they would fully respect that!
I hope you can get something sorted, as I say maybe WFH one day a week or take the baby to the office, try using that as a compromise for more time? xx