Use the category name instead of category slug in permalinks

I did not test this, but this should do what you want. Put the following in your functions.php:

add_filter('rewrite_rules_array', 'new_category_name_rewrite_rule');
function new_category_name_rewrite_rule($rules) {
    $new_rules = array();
    $categories = get_categories();
    foreach ($categories as $category) {
        $cat_name = preg_replace('#\s+#', '-', $category->name);
        $new_rules["https://wordpress.stackexchange.com/".$category->slug."https://wordpress.stackexchange.com/"] = "https://wordpress.stackexchange.com/".urlencode($cat_name)."https://wordpress.stackexchange.com/";
    }
    return $new_rules + $rules;
}