Per the documentation [1], the following command should be used to install CRW 2.1.x on OCP 3.11:

=========================================================================
./bin/crwctl server:start --platform=openshift --installer=operator --domain=apps.ricksche7.lab.upshift.rdu2.redhat.com -n crw2oneone

The results:
✔ Create deployment codeready-operator in namespace crw2oneone...done.
✖ Create CodeReady Workspaces cluster codeready-workspaces in namespace crw2oneone
→ Cannot set property 'ingressDomain' of undefined
› Error: TypeError: Cannot set property 'ingressDomain' of undefined

=======================================================================
Trying again, without the domain:
./bin/crwctl server:start --platform=openshift --installer=operator -n crw2oneone

The results:
Failure. The CRW server pod will not start, it looks to be a TLS problem.

Caused by: java.lang.RuntimeException: Exception while retrieving OpenId configuration from endpoint: https://keycloak-crw2oneone.apps.ricksche7.lab.upshift.rdu2.redhat.com/auth/realms/codeready/.well-known/openid-configuration
at org.eclipse.che.multiuser.keycloak.server.KeycloakSettings.<init>(KeycloakSettings.java:104)
....
....
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target