How do I set/get cookies in a controller (custom module)?

I have a module and I need to set a simple cookie (if not exists). And after each request I need to read the value of the cookie and maybe update.

I have read many articles and tried many ways but no success. The only one, which works, returns a "response" object. But my controller should still work, even after response->header sent/saved.

This is the controller code.

namespace Drupal\my_custom_mod1\Controller;

use Drupal\Core\Controller\ControllerBase;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Cookie;
use Symfony\Component\HttpFoundation\Request;

class myController extends ControllerBase {

    public function main() {
      $cookie = new Cookie(
        "my_cookie_name",                      
        'some value for the cookie',                                       
        (new \DateTime('now'))->modify("+111 day"), 
        "/",                                     
      );
      $res = new Response();
      $res->headers->setCookie($cookie);
      return $res; // if this line deactivated, no cookie will be set

      return [
        '#type' =>      'inline_template',
        '#context' => [
          'my_html_output' => " my text / html output "
        ]
      ];
    }

}