I am getting many fake email addresses signing up

Those are valid Gmail emails, I don't think you can do much about it.

However, I have this class to prevent disposable emails:

<?php
declare(strict_types=1);

namespace src\Infrastructure\Services\Email;

use src\Domain\Authentication\Exceptions\DisposableEmailDomainException;
use src\Domain\Services\Blacklist\DisposableEmailDomainChecker;
use src\Domain\ValueObjects\Security\EmailAddress;

class DisposableDomainList implements DisposableEmailDomainChecker
{
    public function check(EmailAddress $emailAddress): void
    {
        $givenDomain = $emailAddress->domain();

        $disposableDomains = file(base_path('/src/Infrastructure/Services/Email/disposable-domains.txt'), FILE_IGNORE_NEW_LINES);
        foreach ($disposableDomains as $disposableDomain) {
            if (trim($disposableDomain) === $givenDomain) {
                throw new DisposableEmailDomainException($emailAddress->email);
            }
        }
    }
}

You can find lists of disposable emails on GitHub.