Empty entity attributes

The sequence of my actions:
1. Create a model

Code:

<?php namespace App\Models;

use CodeIgniter\Model;

class AdminModel extends Model
{
        protected $table      = 'admin';

        protected $returnType = 'App\Entities\Admin';

        protected $allowedFields = ['last_login', 'last_logout', 'last_ip'];
}

2. Create an entity

Code:

<?php namespace App\Entities;

use CodeIgniter\Entity;

class Admin extends Entity
{

    public function getPassword(){
        return $this->attributes['password'];
    }
   
    public function verify_pass(string $user_password){
        return password_verify($user_password, $this->password);
    }
   
}

3. Initialize the model in the controller.

Code:

$AdminModel = new AdminModel();

4. Trying to get data from the entity.

Code:

$admin = $AdminModel->where('username', $this->request->getPost('username'))
                            ->findAll();

if(empty($admin))
            return redirect()->back()->with('error', array('auth_error' => 'User not found!'));

if( ! $admin->verify_pass($this->request->getPost('password')))
            return redirect()->back()->with('error', array('auth_error' => 'Password incorrect!'));

In case of calling an entity method, I get an error:

Call to a member function verify_pass() on array

When accessing entity fields directly, the resulting value = NULL. And in the dd output, my data is visible.