Magento2 get product brand option text by value in Plugin

I am trying to get the option text from the option value in Plugin, but I can get the value but can’t get the text. May I know any way to do so?

app/code/My/Module/Plugin/DefaultItem.php

<?php

namespace MyModulePlugin;
use MagentoQuoteModelQuoteItem;
use MagentoCatalogApiProductRepositoryInterface;


class DefaultItem
{
protected $productRepository;



public function __construct(
    ProductRepositoryInterface $productRepository,
)
{
    $this->productRepository=$productRepository;
}


public function aroundGetItemData(MagentoCheckoutCustomerDataAbstractItem $subject, Closure $proceed, Item $item)
{
    $data = $proceed($item);

    $productId = $item->getProduct()->getEntityId();

    $brand_value = $this->productRepository->getById($productId)->getCustomAttribute('brand')->getValue();


    $atts = [
        "brand" => $brand_value
    ];

    return array_merge($data, $atts);
}
}

It only returns 13 to the frontend.. but I do want the text for this value…