Too much, quite simply too much !!!!!
I hear this sort of thing so often on GN !! How dare adult children be so unkind and insensitive - who do they think they are!? You feel frightened of your daughter that is a red flag you should take notice of- frightened of your daughter, that is absolutely unacceptable. She is critical of the care you give her children ,
so give her full responsibility of her own children!!!
Talk to your daughter , decide how much ( If anything) care you can give.If your DD can't accept that she must make alternative arrangements for her children and pay for it. Be strong and look after yourself. I took care of GC one day a week for a number of years. My DDs were thankful and grateful and both said "Mum your house your rules " They were never critical and it worked well. So many parents have such a sense of entitlement!!! unbelievable. Remember you are doing your daughter a great favour - it is not the other way round. Her children, her responsibility - simply really. Good luck , be brave and do not be afraid of your daughter, she needs a reality check.