FCOS is based on an OCI image, but requires boot images for release. Build those in konflux. The images are defined  in github.com/coreos/fedora-coreos-config/blob/testing-devel/platforms.yaml

See also https://builds.coreos.fedoraproject.org/browser 

DoD all the necessary artifacts are built.

Look at : https://github.com/osbuild/bootc-image-builder
looks like there might be an existing task for that