BuddyPress.org

Hi, I’ve found a simple way to change that Name field and the sync back to whatever you want it to be.

1. Make sure you have buddypress with extended profiles installed.

2. Create 3 field in the base section of Xprofile
For demo purpose we will name them :

First name
Last name
Nickname
*(you can name them differently but make sure you update the function accordingly)

3. Add that code to the function.php of your child theme.

// modified Xprofile sync.
function xprofile_sync_wp_profile2( $user_id = 0 ) {

	// Bail if profile syncing is disabled
	if ( bp_disable_profile_sync() ) {
		return true;
	}

	if ( empty( $user_id ) ) {
		$user_id = bp_loggedin_user_id();
	}

	if ( empty( $user_id ) ) {
		return false;
	}
    
    // get first name
    $firstname = xprofile_get_field_data('First name',$user_id );

    // get last name
    $lastname = xprofile_get_field_data('Last name',$user_id );
    
    // get nickname
    $nickname = xprofile_get_field_data('Nickname',$user_id );
    
    // create fullname
    $fullname = trim( $firstname . ' ' . $lastname );

	bp_update_user_meta( $user_id, 'nickname',   $nickname  );
	bp_update_user_meta( $user_id, 'first_name', $firstname );
	bp_update_user_meta( $user_id, 'last_name',  $lastname  );

	global $wpdb;

        //you can modify that line to change the displayed name to something else than the nickname
	$wpdb->query( $wpdb->prepare( "UPDATE {$wpdb->users} SET display_name = %s WHERE ID = %d", $nickname, $user_id ) );
}
add_action( 'xprofile_updated_profile', 'xprofile_sync_wp_profile2' );
add_action( 'bp_core_signup_user',      'xprofile_sync_wp_profile2' );
add_action( 'bp_core_activated_user',   'xprofile_sync_wp_profile2' );

4. This script also change the display name to the nickname but you can modify it to whatever you want. just replace $nickname in the indicated line by $firstname, $lastname or $fullname

That’s it