You followed Install and Configure Aria Operations for Logs Agent on vCenter Server for cfapi with SSL. But the logs are captured in the journal, not in Aria Operations for Logs.
Aria Operations for Logs 8.18.x
To send vCenter SSHD logs to Aria Operations for Logs, you will need to configure the vCenter to send syslog to the Aria Operations for Logs cluster.
Please follow the steps in Forward vCenter Server Log Files to Remote Syslog Server.