How to hide custom fields on the menu item form?
hook_entity_base_field_info will add fields to the entire entity. If you want to hide the fields in specific forms, you will have to use a form alter to hide the fields. The following code might be what you are looking for.

/**
 * Implement hook_form_FORM_ID_alter();
 */
function modulename_form_menu_link_content_menu_link_content_form_alter(&amp;$form, FormStateInterface $form_state) {
  $name = $form_state-&gt;getFormObject()-&gt;getEntity()-&gt;getMenuName();
  if ($name !== 'my-menu') {
    $form['show_mobile']['#access'] = FALSE;
    $form['svg_icon']['#access'] = FALSE;
  }
}


Change my-menu with the menu machine name of the only menu that you want the fields to appear on.