Configure your preferred DNS modes to toggle in app and toggle your Private DNS mode from your quick settings panel.

In order to change the Private DNS setting this app requires the 'WRITE_SECURE_SETTINGS' permission.

This permission can only be granted in an ADB shell with the command:
pm grant com.flashsphere.privatednsqs android.permission.WRITE_SECURE_SETTINGS

Check out https://private-dns-qs.web.app/help on the steps to use adb to grant the permission.