Emby only uses LDAP to create users and validate passwords upon login. Emby administrators are always validated via native emby login. https://emby.media/introducing-ldap-support-for-emby.html
Replace dc=example,dc=com with your LLDAP configured domain.
cn=admin,ou=people,dc=example,dc=com
changeme (replace with your password)
ou=people,dc=example,dc=com
replace the emby_user cn with the group name for accounts that should be able to login to Emby, otherwise leave the default (uid={0}).
(&(uid={0})(memberOf=cn=emby_user,ou=groups,dc=example,dc=com))