How to apply_filter / add_filter within 2 others (simultaneous?) add_filter

The ll/tracking_args filter is called by the track_conversion() method, and this function is added to the execution in the constructor of the CustomGF class.

The GFChild class has its own constructor, so the constructor of the base class CustomGF is not executed. In the GFChild constructor also add track_conversion() function to ll/tracking_args filter or call parent constructor.

class GFChild extends CustomGF {

    public function __construct() {
        // Events tracking
        add_filter( 'gform_after_submission', [$this, 'track_conversion'], 10, 2 );

        add_action( 'gform_after_submission_9', [$this, 'submission_business_visit'], 10, 2);
    }
}

Or

class GFChild extends CustomGF {

    public function __construct() {
        //
        // call parent constructor at the beginning or end
        //
        parent::__construct();

        add_action( 'gform_after_submission_9', [$this, 'submission_business_visit'], 10, 2);
    }
}