Security Logs Fortigate

I would like to share only the most relevant security logs from FortiGate to a syslog collector, and I aim to minimize the volume of data being sent.
For example I am interested in User Activity Events, but I would like to filter them further, for example, to include only admin login events.

Is there any official Fortinet documentation that lists the subcategories or log IDs included in “User

Activity Events”, describing their purpose and content?
And more importantly:
Is it possible to apply filters directly on FortiGate (e.g., using CLI) to export only specific subcategories within a log group?

Any example or reference would be greatly appreciated.