Yes, it’s possible with custom code. You can get notification count value with ajax and append any menu item with JS.
Here’s basic example:
Ajax:
jQuery(document).ready(function($){
function updateNotificationCount() {
$.ajax({
url: ajaxurl,
type: 'POST',
data: {
action: 'bp_notification_count'
},
success: function(response) {
if (response.success) {
$('.notification-count').text(response.count);
}
}
});
}
setInterval(updateNotificationCount, 60000);
});
Function:
add_action( 'wp_ajax_bp_notification_count', function(){
wp_send_json(['success' => true, 'count'=> bp_notifications_get_unread_notification_count(bp_loggedin_user_id())])
} );
Don’t forget. This is just an simple example.