Before lockdown I was working as EYP in a private nursery, with two staff per room. We absolutely did cleaning while the children were there. There was no non-contact time, so you had no choice. You had to clean surfaces around the children.
For example, while they were sitting at tables having their lunch or snack time, one EYP would be supervising them, serving food and washing dishes. The other would be sweeping the floor, or hoovering, and cleaning the toilet area, including floor. We took it in turns to prepare snack (making toast, cutting fruit, heating soup) or reading a story to the children sitting together on a mat. You have to plan it so that one person can supervise the children, while the other is busy cleaning or cooking.
I didn't feel it was good care to do it this way, as in cleaning while they were there, but it was what we were told to do.
Toys and cups/plates were regularly sterilized overnight- putting them into a large tub of cold water and milton fluid. So yes, toys could theoretically be washed overnight, ready for the next day - but it is a big effort - lugging the water, rinsing them, drying them. It could be done though.