Need an option of bringing the user names to a consistent (either lower or upper) case before adding them to groups

The issue is particularly related to sync from AD/LDAP since there is no guarantee the user name (from AD side sAMAccountName or userPrincipalName, or mail attributes) is always stored in a canonical form.
It creates a problem since OpenShift/k8s is case sensitive by nature, while LDAP is not.

At this point authentication layer is not a problem since it takes place on LDAP/AD side, but the authorization (ie. groups placed in role bindings) becomes a problem.

From what I was able to gather, there is no plans to change this on the platform side as it is implied the names sourced from the authentication backend are canonical. But I presume the feature can be fairly easy implemented in the group sync operator by introducing a couple parameters, for instance, lower_case: true and upper_case: true to bring all user names to the same case after reading them from AD/LDAP and before placing them in groups.

Start by tracing the group-sync operator's AD/LDAP synchronization path, focusing on where usernames are read and where they are added to groups. Define how the lower_case and upper_case options are configured and validated, then verify that usernames are normalized between those steps and group membership uses the consistent form.