I never thought I’d have DGCs as both my DD’s were quite against and led carefree lives. I could relate to that, not having them until my late 20s/early 30s myself. I had no help from my parents, due to ill health and none from in-laws who couldn’t be bothered, and with other issues, I was unable to work, although I did voluntary work later. Things changed when DD1 had George. She works weekends and SIL is in the emergency services and works shifts. At 66, I was needed to provide regular weekend care - sometimes 2/3 X a month other months not at all.
Guess what? I absolutely loved it and I’m ashamed to admit I’m probably a better Gran than I was a Mum!
Now DD2 has a son and I’ve offered to babysit him one afternoon and evening every week. I don’t have G often for sleepovers now, but pick him up from Pre-School once a week. I don’t consider it much of a dent in my free time and at 71, it’s time with them I shall never get back.
It’s a 50 mile round trip and costs £11 in diesel, so if I have to give up a bottle of wine and a fish and chip takeaway, so be it.
How often do you see your DD and her family as it is? I’d try and discuss things with your DD - was she looked after by your parents/in laws, so you could work?
As others have said - is there an after-school club, a registered child minder or would another Mum take the child home for a couple of hours and you fill in one session a week and say you’ll let her know how that pans out. As she hasn’t got a job yet, that might be harder as it sounds as she’s quite rural? Perhaps your DD will get bored at work too and pack it in? She sounds ‘temperamental’ so I’d tread gently.