> Phone companies have decided you don't need that feature.Bu actually, they can easily implement a nice UI in the settings for the firewall and lock it behind a password, then parents would be able to use it to block individual websites.

iOS: Settings > Screen Time > Content & Privacy Restrictions > Toggle on

Then same area:

- App Installations & Purchases: disallow all

- App Store, Media, Web & Games > Web Content > Limit Adult Websites > Fill in allowlist and/or denylist, or Only Approved Websites and fill in allowlist