If you like to do this in ui with one line of code:
1) add a view mode for user and name it "nodeview":
/admin/structure/display-modes/view/add/user
2) activate the new view mode "nodeview" at the bottom of this page in "Custom Display Settings", then you get a new tab for the view mode "nodeview". Configure which fields are displayed and how they are formatted:
/admin/config/people/accounts/display
3) Use the new view mode to render the author of the node in node preprocess:
$variables['author'] = \Drupal::entityTypeManager()->getViewBuilder('user')->view($variables['node']->getOwner(), 'nodeview');
4) Put the variable in twig
{{ author }}
This method allows full customization in ui and it is fast, because the rendered author gets cached and will be reused in every node referenced.