OpenLDAP is pretty much unrivaled, when it comes to the LDAP-Protocol. Although it is not hard to spot, that the general structure looks a little bit anachronistic in a time of microservices, cloud-native applications and dockerization, it is very reliable, stable and still actively developed.
We use OpenLDAP within a docker-container und interact with it through another docker-container, housing phpLDAPadmin. LDAP is still the gold-standard regarding a centralized, digital directory of the company accounts, structures and permissions and that's why we use it.
It is necessary, however, to install extensions for some features like enhanced group queries, better password algorithms and a few other features, that I'd like to be shipped by default.