While we DO NOT recommend it, you are totally allowed to install ChefDK (normally installed on a workstation) and Chef Server on the same box. They don’t share any configuration so they can definitely co-exist.
However, we don’t recommend this for the more straighforward reason that the chef-server should not also be a workstation - at least there is very little good reason to pursue this path. Workstations are either the machines the developers are using or something in a CI pipeline.
Yes you can but you probably shouldn’t.