ProxyPanel/app/Casts/datestamp.php

<?php

namespace App\Casts;

use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
use Illuminate\Database\Eloquent\Model;

class datestamp implements CastsAttributes
{
    /**
     * Cast the given value.
     *
     * @param  array<string, mixed>  $attributes
     */
    public function get(Model $model, string $key, mixed $value, array $attributes): string
    {
        return date('Y-m-d H:i:s', $value);
    }

    /**
     * Prepare the given value for storage.
     *
     * @param  array<string, mixed>  $attributes
     */
    public function set(Model $model, string $key, mixed $value, array $attributes): int
    {
        return strtotime($value);
    }
}