We have around 50 applications currently configured with LDAP and we have around 20 Domain Controllers. As per the security best practice we have to migrate all these applications from LDAP to LDAPS. Currently, all applications are connected using Domain's "NETBIOS" name so there no need to worry about high availability.
What is the best design approach to achieve high availability for LDAPS?
Prefer not to configure individual DC servers as LDAPS servers in the application. Note: all the servers (DC and application servers) are enrolled in on-prem PKI.