KT-MyPage/app/Email/Members/Members.php

<?php

namespace App\Email\Members;

use App\Email\BaseEmailer;
use App\Kintone\Models\Customer;

abstract class Members extends BaseEmailer
{

    public function __construct(protected ?Customer $customer)
    {
        if ($customer !== null) {
            $this->setEmail($customer->email);
        }
    }

    public function getParams(): array
    {
        return array_merge([
            'customer_name' => $this->customer ? $this->customer->customerName : "",
        ], $this->getMemberParams());
    }

    abstract public function getMemberParams(): array;
}