How do I get the page template name chosen?

I picked the following code from an answer here, https://stackoverflow.com/questions/2544870/remove-main-editor-from-wordpress-edit-page-screen/42093956. I tweaked the code to remove the classic editor on pages using default page template. And added the comments.

function remove_editor_init() {
  $post_id = 0;
  if ( isset( $_GET['post'] ) ) {
    $post_id = $_GET['post'];
  }
  $template_file = get_post_meta( $post_id, '_wp_page_template', TRUE );
  // var_dump($template_file) to see which template the page is using
  // no value on new pages and when template haven't been changed yet
  // default if changed back to default template
  if ( ! $template_file || 'default' === $template_file ) {
    remove_post_type_support( 'page', 'editor' );
  }
}
add_action( 'admin_init', 'remove_editor_init' );

This worked on my local WP install, perhaps you could give it a try?