[zoleest]

Still not worked, but I found out a not too elegant solution. As far as I understand there is an order how the hooks run. There is a hook in class-buddypress.php add_action( 'bp_core_signup_user', array( $this, 'subscribe_from_form' ), 10, 4 ); so I added to my hooks 11, 4 so this is my code now:

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;
	}
    
    global $wpdb;
	
    // Get name from x-fields
    $display_name = xprofile_get_field_data('Név',$user_id );
    

    $wpdb->query( $wpdb->prepare( "UPDATE wphu_users SET display_name = '%s' WHERE ID = %d", $display_name,  $user_id ) );
	
	
}
add_action( 'xprofile_updated_profile', 'xprofile_sync_wp_profile2', 11, 4);
add_action( 'bp_core_signup_user',      'xprofile_sync_wp_profile2', 11, 4);
add_action( 'bp_core_activated_user',   'xprofile_sync_wp_profile2', 11, 4);

And fortunately it works now 🙂 I don’t know if this is a correct way, but work, so I’m okay with it.