By default, the platform does not have this option. You can use the following CSS code.

Please follow the steps below:

    1. Go to BuddyBoss - Theme Options

    2. Under Custom Codes, enable CSS

    3. Append the following:

body:not(.logged-in) .buddypress-wrap .members-list li .list-wrap .last-activity { 
    display:none
}

    4. Save changes.

Note: Any modifications are considered as custom work already. Know more about our Support policy here: https://www.buddyboss.com/support-policy/

Screenshots

Without Code:

With Code: