How to Prevent NextDNS Bypass on Android by Changing 'Private DNS' to 'Automatic'?

Hi everyone,

I've set up NextDNS on my TP-Link router (model TL-WR850N) to filter and secure my network traffic. Everything works well, but I recently discovered that Android devices on my network can bypass NextDNS by simply changing the "Private DNS" setting to "Automatic."

This essentially overrides the router's DNS configuration, allowing the device to use its own default DNS settings.

I’m looking for a way to prevent this bypass and enforce NextDNS for all devices on the network, including Android.