If you have installed a fresh 9.6 on a new server with the default DB Example : Tridion_cm , Tridion_Topology and Tridion_Translation and you wanted to change the config to point to the new DB name or the the upgraded DB in that case yes you need to following the instructions below to update the DB on the following configuration
Content Manager
Run the following to decrypt the database settings (please backup the Content Manager Web.config ):
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -pdf "database" "C:\Tridion\Config"
refer to link
Topology Manager
The database for Topology Manager is configured in %TRIDION_HOME%\TopologyManager\web\Web.config, but you will likely need to decrypt this file to see the settings.
Run the following to decrypt the database settings (please backup the Topology Manager Web.config first):
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -pdf "database" "C:\Tridion\TopologyManager\web"
refer to link
Translation Manager
C:\Tridion\Translation Manager>EncryptTranslationManagerConfiguration.exe /d Passwords decrypted: C:\Tridion\config\TranslationManager.xml
refer to link
As you mentioned you have to update the Micro Services Configuration to point to the new Broker DB and State Store DB for Deployer.
There no no Content Manager DB related configuration that will required to be changed on the CD Side.
Hope it helps !!