Why is Yii2 ActiveRecord not populating object properties?

Question

Yii

Yii2 ActiveRecord does not populate object properties.
That data obviously comes judging by the logs and the filled _attributes property, but if you access it like this: $model->id, then there is NULL. Why is that?
I suspect it's a matter of checks and rules. I tried to enter different validation rules, but did not understand what I was missing.
Thank you!
Simplified to reveal my error:
Sneaker Model

public $id;
public $param1;
public $param2;
public function rules()
{
   return [
       [['id', 'param1', 'param2'], 'safe']
   ];
}

Action

$model= Sneaker::findOne(2);
return $this->render('index', [
    'model' => $model,
]);

Table

id - INT
param1,param2 - VARCHAR

Model inference

app\models\Sneaker Object
(
    [id] => 
    [param1] => 
    [param2] => 
    [_attributes:yii\db\BaseActiveRecord:private] => Array
        (
            [id] => 2
            [param1] => 21
            [param2] => 22
        )

    [_oldAttributes:yii\db\BaseActiveRecord:private] => Array
        (
            [id] => 2
            [param1] => 21
            [param2] => 22
        )

    [_related:yii\db\BaseActiveRecord:private] => Array
        (
        )

    [_errors:yii\base\Model:private] => 
    [_validators:yii\base\Model:private] => 
    [_scenario:yii\base\Model:private] => default
    [_events:yii\base\Component:private] => Array
        (
        )

    [_behaviors:yii\base\Component:private] => Array
        (
        )

)

Answer 1

Remove public properties from the model. The model will automatically make them itself based on data from the database.