If I’m parsing this correctly - no we don’t have documentation for this.
Because kodi is currently only available as a flatpak, it comes with the files that it comes with since you’re not getting it from clearlinux. As such it lacks fullscreen/desktop integration entirely, and the missing service files and desktop units to make this possible are missing.
This page has some good hints as you would go about doing this:
https://kodi.wiki/view/HOW-TO:HOW-TO:Autostart_Kodi_for_Linux
Note, because kodi is a flatpak, you’d have to substitute /usr/bin/kodi with something like /usr/bin/flatpak run tv.kodi.Kodi in the scripts referenced.