Most of infrastructure here runs on redhat if not all and also use centos. So why not add them most brands trusts redhat as a option yes redhat is paid but it provide a good relable service even university have redhat. It is popular no doubt and have all the features like secureboot stable-wayland support and out of the box it have better security.
Kinoite is the same thing as Silverblue, but with KDE instead of GNOME. It can be mentioned alongside Silverblue.
All of the other distributions mentioned are enterprise distributions (RHEL, Alma, Rocky, CentOS), or meant for containerised workflows (MicroOS). I’m not sure there’s a reason to list them seeing as Tumbleweed and Fedora, which are desktop-oriented, are already on the site.
The rest are specifically not recommended. It doesn’t matter what “infrastructure” runs on, because the recommendations on Desktop/PC - Privacy Guides are for desktop computers which have completely different requirements than servers.
I would recommend reading Linux Overview - Privacy Guides, and if you have additional desktop OS recommendations you can create one new thread in the Tools Suggestions category here for each one, as long as reasons why it should be added instead of just a link to their website.