// Hide activity for specific users
function hide_activity_for_specific_user() {
    if (bp_is_user()) {
        $user_id = bp_displayed_user_id();
        if ($user_id == 123) { // Replace 123 with the user ID
            bp_core_load_template('members/single/home');
        }
    }
}
add_action('template_redirect', 'hide_activity_for_specific_user');