Security - DBCS System Login Using OPC User

Hi Team,

We would like your guidance on the recommended security and auditing best practice for user access to our OCI Base Database Service (DBCS) environment.

Currently, administrators(DBA's) connect to the DB system using the opc OS user with a shared SSH key. From there, they switch to the oracle user.

Although individual users are authenticated at the VPN level using their individual credentials, once they connect to the DB system using the shared opc account/SSH key, it becomes difficult for us to identify the actual individual who performed a particular operating-system-level activity.

Also, there are some activities which needs to be performed as sys user, in that case, how can we trace the users. Please detail.