Got several kids at regular public schools (not in US) and their policy never allowed phones during school hours from the start. It is pragmatic and doesn’t cause any drama. The kids get messages home if needed and can collect phones when they leave. It is a relatively normal society where kids walk and ride to school by themselves and parents aren’t obsessed with stalking kids or bubble wrapping them.

Schools have a duty of care and sadly are as much baby sitters for working parents as they are places of learning and phones create more problems than they introduce opportunities.