How to get User Profile form?
You need to use it's namespace, like

use Drupal\user\ProfileForm;

 ..

$form = \Drupal::formBuilder()-&gt;getForm(ProfileForm::class);


Or prefix the class, like

$form = \Drupal::formBuilder()-&gt;getForm(Drupal\user\ProfileForm::class);


Or get it by 'name', like

 $form = \Drupal::formBuilder()-&gt;getForm('Drupal\user\ProfileForm');





  To fix your error, you need to pass a user object there, like this
  (for the current user)


Drupal::formBuilder()-&gt;getForm(ProfileForm::class, Drupal::currentUser());