Oracle recommends that you use appropriate operating system groups and users for all installations where you specify separate Oracle Home Users:

You can choose from the following operating system groups and users, as per your configuration:

Separate Oracle Installation users for each Oracle software product (typically, oracle, for the Oracle Database software, and grid for the Oracle Grid Infrastructure software.

You must create at least one Oracle Installation user the first time you install Oracle software on the system. This user owns the Oracle binaries of the Oracle Grid Infrastructure software, and you can also use this same user as the Oracle Installation user for the Oracle Database or Oracle RAC binaries.

The Oracle Installation user for Oracle Database software has full administrative privileges for Oracle instances and is added to the ORA_DBA, ORA_ASMDBA, ORA_HOMENAME_SYSBACKUP, ORA_HOMENAME_SYSDG, ORA_HOMENAME_SYSKM, and ORA_HOMENAME_SYSRAC groups. Oracle Home users are added to the ORA_HOMENAME_DBA group for the Oracle home created during the installation. The ORA_OPER and ORA_HOMENAME_OPER groups are created, but no users are added to these groups during installation.