Set up Die Ratel
Start with the router if you can: it protects everything on the network at once. Then lock the DNS setting on children's phones so it cannot be changed. Just try get past, boet!
Router (whole home or office)
One change covers every device on the Wi-Fi.
Android: Private DNS
No app needed on Android 9 and newer.
iPhone, iPad and Mac: DNS profile
Install an encrypted-DNS profile; can be locked with Screen Time.
Windows 11: encrypted DNS
Built-in DNS over HTTPS.
Chrome, Edge, Firefox, Brave
Set the secure DNS provider in the browser.
When you are done, open Is it working? to confirm the filter is active.