Module development and code questions

in drupal 9.2.7 I use a callback to update an entity reference field. The code I placed in version 8.8 works. I don't know if anything has changed in the 9.
Below is the code I use

Dear all,

I would like to have all shared albums of a certain google account automatically into a Drupal website.
I was able to establish a connection with 'Google_photos_api' and show all shared albums on site with code below. (I copied code below to a 'Simple page' - and use Full-HTML (source-code)

How do I get the VSCode Intelliphense extension to work with Drupal 8,9?

Do Have to copy the Drupal core directory inside my project? What about composer? 

Hi there, I followed the most recent drupal form api tutorial from the official website.

But for some reason I am getting this error: The website encountered an unexpected error. Please try again later.

I also don't know what the problem is, because I'm not getting any regular php/drupal errors.

Here's my code:

I'd like to apply the same autowire mechanism used for services to classes implementing ContainerInjectionInterface (ex: forms), to reduce boilerplate code.
For example I have currently:

The following is not working: (The description and javascript is working)

function bncreports_form_user_register_form_alter(&$form, FormStateInterface $form_state, $form_id)
{
  $form['account']['name']['#description'] = 'Use Email address as your username';
  $form['account']['name']['#attributes'] = ['onblur' => 'this.value=this.value.toLowerCase();'];
  $form['field_district']['#required'] = true;
  dump($form);
}

The field_district filed is not required when it should be.