Return an existing record for factory from DB in Laravel 8.x

I have some pre-seeded achievements in my DB that I'm not sure how to return via Laravel 8's factory. WebUser and Achievements have a Many-to-many relationship, which I also couldn't figure out from the docs on how to declare properly.

I'd like the WebUser to have an Achievement - that was returned from the DB randomly - attached to its relations via factories

I'm instantiating the WebUser like so:

$webUser = WebUsers::factory()
        ->has(Achievement::factory()->setClass('Onboarded'))
        ->create();

Because of the pre-seeded values, of course this throws an integrity constraint violation - duplicate entry - because the Achievements classes' names should be unique.

The WebUser's definition is simple:

public function definition()
{
    return [
        'web_user_id' => $this->faker->unique()->uuid,
        'coins' => random_int(0, 1000),
        'total_spins' => random_int(0, 100),
        'total_wins' => random_int(0, 1000),
        'total_loss' => random_int(0, 100)
    ];
}

My question is, how to write the Achievement factory in order not to create a new achievement, but rather return an already existing one from the DB.

AchievementFactory's state and definition are the following:

    public function definition()
{
    return [
        'class' => $this->getRandomAchievementClass() // returns a random class name from existing ones
    ];
}

public function setClass($class)
{
    return $this->state(function () use ($class) {
        return [
            'class' => $class
        ];
    });
}