Devices such as phones come with an option when you start the device asking simply is this for a child or an adult. Your router generally these days comes with a parental filter option on start up too. Heck we have chatgpt that can guide a parent through setting up a system if they want something more custom.
If people want to push, they should just push to make these set up options more ubiquitous, obvious and standardized. And perhaps fund some advertising for these features.
Router parental filters are accountability sinks. They don't actually work, and they can't because we spent the last 20 years redesigning network protocols to prevent middle boxes from tampering with connections.