RMAN/LOGICAL BACKUP create an Oracle account
To create database user for backup and assign the appropriate roles in Oracle DB

CREATE USER DBBACKUP IDENTIFIED BY ;
GRANT UNLIMITED TABLESPACE TO DBBACKUP;
GRANT AQ_ADMINISTRATOR_ROLE TO DBBACKUP;
GRANT SYSDBA TO DBBACKUP;
GRANT CONNECT TO DBBACKUP;
GRANT CONNECT TO DBBACKUP;
ALTER USER DBBACKUP DEFAULT ROLE ALL;
ALTER USER DBBACKUP DEFAULT TABLESPACE SYSTEM;

Validate the roles and privileges with the below command after login as backup user DBBACKUP

select * from session_privs;
select grantee, privilege from DBA_SYS_PRIVS where
grantee = ‘DBBACKUP’ Union
select grantee, GRANTED_ROLE from DBA_ROLE_PRIVS where grantee = ‘DBBACKUP’;