Change page title from Views preprocess function
I don't think hook_preprocess_views_view() or hook_preprocess_page_title() is good ways in your case. You can use hook_views_pre_render

/**
 * Implements hook_views_pre_render().
 */
function MYMODULE_views_pre_render(ViewExecutable $view) {

  if ($view-&gt;id() == 'VIEW_ID') {
    $arg = $view-&gt;args; // Argument from view. 
    $default_title = $view-&gt;getTitle(); // Get view title.
    $view-&gt;setTitle('New title'); // Set new title
  }
}


All variables you need in here.