I prefer one database server instance hosting different databases, for each client service one.

FreeBSD

Unattended updates can be tricky.

Think of config changes which need manual adjustment, or a broken update. This is something you would probably not like to happen at night without notice. Could easily break your vital systems (e.g. homeassistant, authentication, vaults…)

OpenLDAP and Eclipse with Apache Directory Studio as plugin for GUI purposes