Create product attribute with source - Magento 2

app/code/Vendor/Module/Setup/Patch/Data/AddBackorderCategoryProductAttribute.php

<?php
namespace Vendor\Module\Setup\Patch\Data;

use Magento\Catalog\Model\Product;
use Magento\Eav\Model\Entity\Attribute\Backend\ArrayBackend;
use Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface;
use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\Patch\DataPatchInterface;
use Magento\Framework\Setup\Patch\PatchRevertableInterface;
use Vendor\Module\Model\Config\Source\Category;

class AddBackorderCategoryProductAttribute implements DataPatchInterface, PatchRevertableInterface
{
    const PRODUCT_ATTRIBUTE = 'backorder_category';

    /**
     * @var ModuleDataSetupInterface
     */
    private $moduleDataSetup;
    /**
     * @var EavSetupFactory
     */
    private $eavSetupFactory;

    /**
     * Constructor
     *
     * @param ModuleDataSetupInterface $moduleDataSetup
     * @param EavSetupFactory $eavSetupFactory
     */
    public function __construct(
        ModuleDataSetupInterface $moduleDataSetup,
        EavSetupFactory $eavSetupFactory
    ) {
        $this->moduleDataSetup = $moduleDataSetup;
        $this->eavSetupFactory = $eavSetupFactory;
    }

    /**
     * {@inheritdoc}
     */
    public function apply()
    {
        $this->moduleDataSetup->getConnection()->startSetup();
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $this->moduleDataSetup]);
        $eavSetup->addAttribute(
            Product::ENTITY,
            self::PRODUCT_ATTRIBUTE,
            [
                'type' => 'int',
                'label' => 'Backorder Category',
                'input' => 'select',
                'source' => Category::class,
                'frontend' => '',
                'required' => false,
                'backend' => ArrayBackend::class,
                'sort_order' => '30',
                'global' => ScopedAttributeInterface::SCOPE_STORE,
                'default' => null,
                'visible' => true,
                'user_defined' => true,
                'searchable' => false,
                'filterable' => false,
                'comparable' => false,
                'visible_on_front' => false,
                'unique' => false,
                'apply_to' => '',
                'group' => 'General',
                'used_in_product_listing' => true,
                'is_used_in_grid' => false,
                'is_visible_in_grid' => false,
                'is_filterable_in_grid' => false,
                'option' => ''
            ]
        );

        $this->moduleDataSetup->getConnection()->endSetup();
    }

    public function revert()
    {
        $this->moduleDataSetup->getConnection()->startSetup();
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $this->moduleDataSetup]);
        $eavSetup->removeAttribute(Product::ENTITY, self::PRODUCT_ATTRIBUTE);

        $this->moduleDataSetup->getConnection()->endSetup();
    }

    /**
     * {@inheritdoc}
     */
    public function getAliases()
    {
        return [];
    }

    /**
     * {@inheritdoc}
     */
    public static function getDependencies()
    {
        return [];
    }
}

app/code/Vendor/Module/Model/Config/Source/Category.php

<?php
namespace Vendor\Module\Model\Config\Source;

use Magento\Catalog\Model\ResourceModel\Category\CollectionFactory as CategoryCollectionFactory;
use Magento\Eav\Model\Entity\Attribute\Source\AbstractSource;
use Magento\Eav\Model\Entity\Attribute\Source\SourceInterface;
use Magento\Framework\Data\OptionSourceInterface;

class Category extends AbstractSource implements OptionSourceInterface, SourceInterface
{
    /**
     * @var CategoryCollectionFactory
     */
    private $categoryCollectionFactory;

    /**
     * Category constructor.
     * @param CategoryCollectionFactory $categoryCollectionFactory
     */
    public function __construct(
        CategoryCollectionFactory $categoryCollectionFactory
    ) {
        $this->categoryCollectionFactory = $categoryCollectionFactory;
    }

    /**
     * @return array|mixed
     * @throws \Magento\Framework\Exception\LocalizedException
     */
    public function getAllOptions()
    {
        $collection = $this->categoryCollectionFactory->create();
        $collection->addAttributeToSelect('*');
        $collection->addIsActiveFilter();

        foreach ($collection as $category) {
            $options[] = [
                'value' => $category->getId(),
                'label' => $category->getName() . ' (ID:' . $category->getId() . ')'
            ];
        }
        return $options;
    }
}