I had a heck of a time understanding why I was not seeing the NextDNS profile I downloaded from my NextDNS configuration page. I used the Kagi developed web browser Orion to download the .CER file. Once I moved the file out of the download directory and into the files root directory, the .CER was available to install.
Once you install your trusted certificate (Settings > General > About > Certificate Trust Settings), you have to enable that certificate.
