In symfony 5 - trouble with autowire and configuration

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Symfony

I switched from asp.net core and Laravel to Symfony5. And I have a problem with the my service and the configuration system.Dependency Injection still works even though I turned off autowiring. Also, the settings inside the dev folder do not override those in service.yaml!

What I have tried:

At the src\Services location, I created a simple php class as a simple service:

<pre lang="PHP">
<pre><?php
//src/Services

namespace App\Services;

class HelloService
{
    public function sayHello($name='John Doe')
    {
        return 'Hello ' . $name;
    }
}

and TestServiceController to test the service:

<pre><?php
//src/Controller
namespace App\Controller;

use App\Services\HelloService;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class TestServiceController extends AbstractController
{
    #[Route('/test', name: 'test_service')]
    public function index(HelloService $hs): Response
    {
        return new Response($hs->sayHello());
    }
}

Based on Symfony documentation, since I created the service inside the src\ folder
my service should be automatically visible to the container and supports autowiring by default (services.yaml default conf.). When an application is launched in a dev environment everything works ok and I get it on the website:

Hello John Doe

However, now if I want to turn off autowiring, inside the service.yaml file I wrote:

services:
....
.... rest configs
....
    App\Services\HelloService:
        autowire: false

and when I run command:

php bin/console debug:container HelloService

i get confirmation that autowired no

However, the app still works and launches:

Hello John Doe

What bothers me is the following:
As I understood the documentation, an exception should be happened becose autowiring now is shutdown, automatic Dependency Injection should be disabled now and specifying the type of class-HelloService in the controller method - public function index (HelloService $ hs) it should be not work and application should throw an exception but it still works OK! Why? !!!

----
Also, overriding service settings does not work for me.
For example, if I have a setting in service.yaml:

services:
....
.... rest configs
....
    App\Services\HelloService:
        autowire: true

and if I want to override default configs in services.yaml and turn off autowire in a dev environment,

\config\packages\dev\HelloService.yaml :

services:
  App\Services\HelloService:
    autowire: false

when I run

php bin/console debug: HelloService container

Im still get autowired: yes

Shouldn't the configurations defined within \packages\dev\<service>.yaml override those in service.yaml ?!

Also, the configurations defined in service_dev.yaml do not override those defined in service.yaml while the documentation claims otherwise or I misunderstood something.
Thank you very much in advance.