It's irksome that these laws and bills in multiple countries are trying to put limits on the general purpose computer. It's the wrong solution and arguably put forward in bad faith.
If you want access control, the appropriate point for regulation is with ISPs and cellular providers, and the appropriate mode of regulation is requiring these companies to provide choice and education for families, and awareness of liability.
Require ISPs and cellular network providers to offer a standard set of controls to their customers informing the common person (in common language) who is using those connections and what they are doing with them. For ISPs, this looks like an option for a router with robust access controls, designating some devices (based on MAC address) as belonging to children and filtering those devices' network requests at the network gateway, or filtering one hop up onto the provider's infrastructure (e.g. the ONT for fiber connections). For cellular providers, it looks like an app available to parents' devices and similar filtering for devices designated as belonging to children (based on IMEI).
When a family signs up for Internet service, either at-home access or cellular data, the provider must give both parents a presentation about these tools, and about the liability the parents face for allowing their children unsupervised, latchkey access to adult content, no different than allowing children to drink alcohol.
It may even make sense to require ISPs and cellular providers to track MAC addresses and IMEIs of devices their own customers designate as "for children" and make those providers liable for not filtering Internet for those devices, and also liable for allowing targeted advertising against those devices.
I don't think achieving that setup is likely, but it's fundamentally the right way to solve this problem, and parents are pushing for a solution one way or another. I don't love it, but if it's coming almost inevitably we should at least push to do it right. It's a dead-end, losing strategy to blanket oppose one solution to legislators and provide no alternative. I write all of that as someone who values privacy and liberty, both in meatspace and cyberspace.