Hiding machine name from a form temporarily only during validation

I’m looking for a solution to hide machine_name from a form temporarily (only during validation) and restore it afterward.

When the form has validation with errors the machine name appears (with a different label like: "Internal name"). I need to hide the machine name while validation has errors. And also force the user to change the name of the source to avoid errors.

My solution (that still not working) is:

1. In form_alter() add a new validation function callback in form alter before calling to the validation add  $form["name"]["access"] = FALSE; //to hide the machine name from the form.
2. In the validation function check if the element name is unique.

if false (meaning error)
  $form_state->setError()
else
  $form["name"]["access"] = TRUE;
  $form_state->setRebuild(TRUE);

This works to the point that the machine name is hidden and when there is an error it shows my error message.

The problem is that if the name of the element is unique (meaning there are no validation errors) - It doesn't save the form.

What am I missing here? 

[I'm using drupal 9 on The Apigee Developer Portal Kickstart distribution]

By denying access you are removing the form element and there will be no value submitted.

For hiding you can try CSS

$form['name']['#attributes']['class'][] = 'visually-hidden';

or transform the form elment to #type = hidden.