How to customize the pagination

Hi,

I'm not familiar with template development of Joomla 4, but I suspect this is still the same as on Joomla 3.
Supposing it's still the same, you need to create a pagination.php file in the main folder of your Joomla template and define the _list_render function to generate the HTML you want:
forum.joomla.org/viewtopic.php?t=834931

Now, looking at your situation, I think you should be able to do it with just CSS code you could add to your template. Here a good start:

li.active a.page-link {
    display: block;
}
li.active a.page-link:before {
    content: 'Page ';
}
a.page-link.next, a.page-link.prev, li.active a.page-link {
    display: block;
}