I was a nanny who took my child
DD was 3 and turned 4 in the year I did it.
I was nanny to two children, one the same age as DD and one a year younger.
It was a nightmare. The kids had developmental delay (due to lazy parenting - mum didn't want to potty train incase they peed on the carpet. So they never came out of nappies. She wanted me to train them but they weren't allowed accidents. She would put a dummy in their mouth if they ever made any kind of noise, even at 4 years old. Didn't eat properly and didn't have the norms you'd expect, for example they'd panic and cry if they had a runny nose as didn't know to get or ask for a tissue. Loads more of examples and entirely NOT the kids faults)
Anyway DD was very well behaved, the parents thought she was a lot older due to the difference in her development, I tried to explain the typical development stages but parents not interested.
The kids couldn't share and were violent to each other and DD quite badly. They were clearly desperate for their parents attention but never received it. They would be sat with a dummy in their mouth and an iPad while parents did what they wanted. 24/7.
I quit as I wasn't able to make any positive impact due to how restrictive the parents were and I felt the kids were suffering. I advised them to put the kids into a nursery. They did, and they thrived at nursery.
Sorry that turned into a massive rant!