Custom Product attribute issue magento 2

Question

Hi i have a custom prodcuct attribute i want to show the same attribute in category also under the same group is it possible below is my code please suggest me how to achieve this

<?php
namespace Vendor\Module\Setup;

use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface;

class InstallData implements InstallDataInterface
{
    /**
     * EAV setup factory
     *
     * @var EavSetupFactory
     */
    private $eavSetupFactory;

    /**
     * Init
     *
     * @param EavSetupFactory $eavSetupFactory
     */
    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    /**
     * {@inheritdoc}
     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
     */
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

        /**
         * Add attributes to the eav_attribute
         */
        $eavSetup->removeAttribute(\Magento\Catalog\Model\Product::ENTITY, 'miscellaneous');
        $eavSetup->removeAttribute(\Magento\Catalog\Model\Product::ENTITY, 'miscellaneous');

        $eavSetup->addAttribute(
            \Magento\Catalog\Model\Product::ENTITY,
            'miscellaneous_meta',
            [
                'group' => 'Search Engine Optimization',
                'type' => 'text',
                'backend' => '',
                'frontend' => '',
                'label' => 'Meta Miscellaneous',
                'input' => 'text',
                'class' => '',
                'source' => '',
                'global' => ScopedAttributeInterface::SCOPE_GLOBAL,
                'visible' => true,
                'required' => false,
                'user_defined' => false,
                'default' => '',
                'searchable' => false,
                'filterable' => false,
                'comparable' => false,
                'is_used_in_grid' => true,
                'visible_on_front' => false,
                'used_in_product_listing' => false,
                'unique' => false
            ]
        );

        
    }
}

update

<?php
namespace Vendor\Module\Setup;

use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface;

class InstallData implements InstallDataInterface
{
    /**
     * EAV setup factory
     *
     * @var EavSetupFactory
     */
    private $eavSetupFactory;

    /**
     * Init
     *
     * @param EavSetupFactory $eavSetupFactory
     */
    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    /**
     * {@inheritdoc}
     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
     */
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

        /**
         * Add attributes to the eav_attribute
         */
        $eavSetup->removeAttribute(\Magento\Catalog\Model\Product::ENTITY, 'miscellaneous');
        $eavSetup->removeAttribute(\Magento\Catalog\Model\Product::ENTITY, 'miscellaneous');

        // $statusOptions = 'Rbj\ProductAttribute\Model\Config\Source\StatusOptions';
        $eavSetup->addAttribute(
            \Magento\Catalog\Model\Product::ENTITY,
            'miscellaneous_meta',
            [
                'group' => 'Search Engine Optimization',
                'type' => 'text',
                'backend' => '',
                'frontend' => '',
                'label' => 'Meta Miscellaneous',
                'input' => 'text',
                'class' => '',
                'source' => '',
                'global' => ScopedAttributeInterface::SCOPE_GLOBAL,
                'visible' => true,
                'required' => false,
                'user_defined' => false,
                'default' => '',
                'searchable' => false,
                'filterable' => false,
                'comparable' => false,
                'is_used_in_grid' => true,
                'visible_on_front' => false,
                'used_in_product_listing' => false,
                'unique' => false
            ]
        );

        $eavSetup->addAttribute(
    \Magento\Catalog\Model\Category::ENTITY,
    'miscellaneous_meta',
        [
            'type' => 'text',
            'backend' => '',
            'frontend' => '',
            'input' => 'text',
            'visible'  => true,
            'default'  => '',
            'required' => false,
            'global'   => ScopedAttributeInterface::SCOPE_STORE,
            'group' => 'Search Engine Optimization'
        ]
    );
    }
}

Answer 1

it's not possible to share same attribute between entities.

But you can create same attribute for different entities.

Here an example on how to create product attribute:

public function execute()
{
    $eavSetup->addAttribute(
        \Magento\Catalog\Model\Product::ENTITY,
        'miscellaneous_meta',
        [
            'type' => 'varchar',
            'group' => 'Search Engine Optimization',
            'backend' => '',
            'frontend' => '',
            'input' => 'text',
            'class' => '',
            'source' => '',
            'global' => ScopedAttributeInterface::SCOPE_GLOBAL,
            'visible' => true,
            'required' => false,
            'user_defined' => true,
            'default' => '',
            'searchable' => false,
            'filterable' => false,
            'comparable' => false,
            'visible_on_front' => true,
            'used_in_product_listing' => true,
            'unique' => false,
            'apply_to' => ''
        ]
    );
}

Here example for categories:

public function execute()
{
    $eavSetup->addAttribute(
    \Magento\Catalog\Model\Category::ENTITY,
    'miscellaneous_meta',
        [
            'type' => 'varchar',
            'backend' => '',
            'frontend' => '',
            'input' => 'text',
            'visible'  => true,
            'default'  => '',
            'required' => false,
            'global'   => ScopedAttributeInterface::SCOPE_STORE,
            'group' => 'Search Engine Optimization'
        ]
    );
}

UPDATE

which version of Magento 2 are you using? because on 2.3 "setup install" it's deprecated, you should use Patch Data, following best practice magento: https://devdocs.magento.com/guides/v2.4/extension-dev-guide/declarative-schema/data-patches.html

Cheers