Combine displayName attribute from givenName and sn in OpenLDAP?

Question

In my OpenLDAP 2.4.40 directory I maintain given names in the givenName and surnames in the sn attribute, defined by object classes inetOrgPerson and person respectively.

To avoid maintenance effort I'd like displayName (preferably, but any attribute would be acceptable) to be calculated from givenName sn.

How do I do this?

I am aware of OpenLDAP overlays, but from the list only the remap/rewrite overlay seems remotely useful, however from my understanding it will not do what I want.

I am also aware that joining could be done programmatically in the client application, which is also not what I want.