8 – How do I add a button with a custom redirect to a node view?

I’d like to add a “More info” button to the bottom of a node view. The button should redirect the user to a URL based on the current node, e.g. node/1/info:

 * Implements hook_node_view
 * Add the "More Info" button to idea content

function implementations_node_view(array &$build, DrupalCoreEntityEntityInterface $entity, DrupalCoreEntityDisplayEntityViewDisplayInterface $display, $view_mode) {

  $build('implementations_addition') = (
    '#type' => 'button',
    '#value' => t('More Info'),
    '#submit' => ('implementations_submit_impl'),
    '#weight' => 1000,
    '#attributes' => (
      'class' => ('btn', 'btn-primary'),
      //'onclick' => "location.href='https://google.com'" # dirty hack I really want to avoid

function implementations_submit_impl(array $form, DrupalCoreFormFormStateInterface $form_state) {
  # just a mock redirect for now
  return new SymfonyComponentHttpFoundationRedirectResponse(DrupalCoreUrl::fromRoute('user.page'));

The above code results in the button correctly appearing, but when I click on it, nothing happens. What am I doing wrong here? Is there a better way?