Apple devices, both iOS and macOS, have great and fairly easy to use remotely-managed parental controls (Microsoft may too, IDK) that can do things like apply all sorts of limits to allowed websites or apps during certain periods of the day, but god-damned school-provided-and-managed devices blow holes through any plan to use that for those purpose. Even if the school sends home devices in your ecosystem, you won't be able to configure the parental controls on them, and their settings are always way too loose.
Which leaves you with your network as the place you have to manage all of that, which is a much bigger pain in the ass.