Is it complex? Yes. Is it more complex than k8s? Probably. However, are there multiple open source distros outside of RDO (which is not actually a distro and is instead packaging--see tripleo for a distro like solution based on RDO). MaaS is not an OpenStack distro; it's a way to manage baremetal nodes that OpenStack is then deployed onto using other Canonical related tools. That said, selecting a way to deploy and manage openstack is complex, but the same with k8s.