How to create link to a view
As you want to create url object from a path instead of route, use the function fromUri() instead of fromRoute().

$url  = Url::fromUri('internal:/progetti');
$variables['items'][]['value'] = array(
  '#type' =&gt; 'link',
  '#title' =&gt; array('#value' =&gt; 'sergio'),
  '#url' =&gt; $url,
);


In fromUri() function you need to pass the URI of the resource including the scheme. For user input that may correspond to a Drupal route, use internal: for the scheme.