It’s an alternative shell for Plasma, so theoretically you should be able to do anything in it that you can do in Plasma.

On my Arch box it installed a minimal set of Plasma utilities to support it, which means my setup is still very limited (and I can’t turn off screen lock!), but I haven’t tried if it would change if offered a full Plasma install.

I can most certainly launch Steam, Kodi, Jellyfin etc.