Extending MailMessage class in laravel

I have a situation in which I need to customize or rather add some buttons in emails going to a specific set of users, let's say we have normal users and investors and I have some notification classes that send emails to investors. In these Notification classes, I'll need to add some links they can click on to view some resources for them only. I created a MailMessage class that extends Laravel's MailMessage class with a method target()

<?php

namespace App\Notifications\Messages;

use Illuminate\Notifications\Messages\MailMessage as MessagesMailMessage;

class MailMessage extends MessagesMailMessage
{
    /**
     * The target audience.
     *
     * @var string
     */
    public $target;

    /**
     * Set the target audience for the mail message.
     *
     * @param  string  $target
     * @return $this
     */
    public function target(string $target)
    {
        $this->target = $target;

        return $this;
    }
}

then in the notification class, I used the new MailMessage class which I created that still extends Laravel's MailMessage

use App\Notifications\Messages\MailMessage;
class InvestorNotification extends Notification implements ShouldQueue
{
    use Queueable;

    protected $investment;

    /**
     * Create a new notification instance.
     *
     * @return void
     */
    public function __construct(Investment $investment)
    {
        $this->investment = $investment;
    }

    /**
     * Get the notification's delivery channels.
     *
     * @param  mixed  $notifiable
     * @return array
     */
    public function via($notifiable)
    {
        return ['mail'];
    }

    /**
     * Get the mail representation of the notification.
     *
     * @param  mixed  $notifiable
     * @return \Illuminate\Notifications\Messages\MailMessage
     */
    public function toMail($notifiable)
    {
     
        return (new MailMessage())
                    ->target('investor')
                    ->line('Thank you for choosing us!');
    }

but in the /resources/view/vendor/notification/email.blade.php I tried to check if $target exists and then display the buttons but the $target is not returning as undefined please help in any way you can