elgg_view_menu('pages_nav',[]) means that somewhere a menu with pages_nav name is registered.

You can easily find it using 'Developer tools' plugin then 'Inspect -> Events'.

So you can find this event and it shows us the menu is registered in this class.

Now you can (1) override this class using same path, or (2) unregister this class and register your own in the custom plugin (best choice).

Add sort_by parameter to $children = elgg_get_entities code:

$children = elgg_get_entities([
      'type' => 'object',
      'subtype' => 'page',
      'metadata_name_value_pairs' => [
          'name' => 'parent_guid',
          'value' => $next_level_guids,
          'operand' => 'IN',
       ],
      'batch' => true,
      'sort_by' => [
        'property_type' => 'metadata',
        'property' => 'title',
        'direction' => 'ASC',
      ],

]);

Thanks once again for the answer. The tip with the "developer tools" is excellent. That helps a lot.

I followed your advice, found the file (I don't know how I missed it before, since it's quite visible within the folder structure) and tried updating it via "my plugin", just like I did with for previous topics, but unfortunately,  nothing happened this time. I also tried overriding the original file "PagesNav.php" within the "pages" plugin which always worked for my previous topics, but it also didn't change the sorting order.

I will continue to investigate this. For now, I just wanted to post an update, in case someone else might follow this thread.

In your custom plugin:

elgg-plugin.php

'events' => [
    'register' => [
         'menu:pages_nav' => [
             'Elgg\Pages\Menus\PagesNav::register' => ['unregister' => true],
             '\MyPlugin\Pages\Menus\PagesNav::register' => ['priority' => 800],
         ],
    ],
],

Thank you once again for your patience and clear explanations. I appreciate it and I understand now how register/unregister works and should be able to apply it correctly by myself from now on.

I followed your instructions and my site uses my own PagesNav now for the sidebar (as tested by making small changes there). Unfortunately, the sorting is still done via ID though, like this:

Item 1: pages/view/586/rrr

Item 2: pages/view/592/sss

Item 3: pages/view/598/ddd

I will play around with the code to see if I can find the reason, but my guess is that you will be faster. ;)

I just wanted to ask you about this )

There is a separate event for this menu.

You can also unregister it in your plugin instead of deactivating the plugin.

'Elgg\Pages\Menus\PagesNav::register' => ['unregister' => true],
'\ColdTrick\PagesTools\Menus\PagesNav::orderPagesNav' => ['unregister' => true],
'\MyPlugin\Pages\Menus\PagesNav::register' => ['priority' => 800],

In future, use 'Developer tools' plugin to inspect ALL same events