OpenShift supports wildcard routes but it is not enabled by default. If you create a route for *.domain.com without enabling it, you will see a Rejected status for your route.
To enable wildcard route, you need to edit default IngressController in openshift-ingress-operator namespace and add the following to the spec.
# oc -n openshift-ingress-operator edit ingresscontroller default
spec:
...
routeAdmission:
wildcardPolicy: WildcardsAllowed
When you edit IngressController, router pods in openshift-ingress will be restarted to apply the changes.