Magento 2.4: Custom image role dropdown save in database

I created a custom image role drop down.

I am trying to save its value into ‘catalog_product_entity_media_gallery_value’ table by using the observer event ‘catalog_product_save_after’:

<?php

namespace HotcoffeeImageCustomRoleObserver;

use MagentoFrameworkEventObserverInterface;

class Productsaveafter implements ObserverInterface
{
    protected $request;
    protected $resource;

    /**
     * 
     * @param MagentoFrameworkAppRequestInterface $request
     * @param MagentoFrameworkAppResourceConnection $resource
     */
    public function __construct(
    MagentoFrameworkAppRequestInterface $request, MagentoFrameworkAppResourceConnection $resource
    ) {
        $this->request = $request;
        $this->resource = $resource;
    }

    public function execute(MagentoFrameworkEventObserver $observer) {

//         $galleryPart = array();
        $data = $this->request->getPostValue();
        $objectManager = MagentoFrameworkAppObjectManager::getInstance();
        $messageManager = $objectManager->create('MagentoFrameworkMessageManagerInterface');
        $array_element = 0;

        if (isset($data['product']['media_gallery']['images'])) {

        $images = $data['product']['media_gallery']['images'];
        foreach ($images as $value) {
            if ($value['value_id'] == "") {
                $array_element++;
            }
        }

        $productCollection = $objectManager->create('MagentoCatalogModelResourceModelProductCollectionFactory');
        $collection = $productCollection->create();
        $collection->getSelect()->join(
            array('value_entity' => $collection->getTable('catalog_product_entity_media_gallery_value')),
            'e.entity_id = value_entity.entity_id',
            array('value_id')
        );
        $collection->getSelect()->join(
            array('value_data' => $collection->getTable('catalog_product_entity_media_gallery')),
            'value_entity.value_id = value_data.value_id',
            array('value')
        );

        $product = $observer->getProduct();
        if(empty($data['id'])){
          $id = $product->getId();
        }else{
          $id = $data['id'];
        }
        $product = $collection->addFieldToFilter('entity_id', ['eq' => $id]);
        $collection_updated = array_slice($product->getData(), "-" . $array_element, $array_element, true);
        $new_image_id = [];
        foreach ($collection_updated as $key => $value) {
            $new_image_id[] = $value['value_id'];
        }
        try
        {
            $getGalleryPart = [];
            $resource = $objectManager->get('MagentoFrameworkAppResourceConnection');
            $connection = $resource->getConnection();
            $tableName = $resource->getTableName('catalog_product_entity_media_gallery_value');
            foreach ($images as $image) {

                print_r($image['GalleryPart_part']);
                //if ($image['removed'] != "") {
                // if(!empty($image['removed'])){  
                //     $sql = "DELETE FROM " . $tableName . " WHERE value_id =" . $image['value_id'];
                //     $connection->query($sql);
                // }
                // if ($image['value_id'] == "") {
                //     if (!isset($image['store_id']) || $image['store_id'] == "") {
                //         $store_id = '0';
                //     } else {
                //         $store_id = $image['store_id'];
                //     }
                //     $getGalleryPart[] = $image['GalleryPart_part'];
                // } else {
                //     $sqlGalleryPart = "update " . $tableName . " set GalleryPart_part = " . $image['GalleryPart_part'] . " where value_id = " . $image['value_id'];
                //     $connection->query($sqlGalleryPart);
                // }
            }
            exit;

            if ($array_element > 0) {
                $count = 0;
                foreach ($collection_updated as $key1 => $value1) {
                    $collection_updated[$key1]['new_GalleryPart_part'] = $getGalleryPart[$count];
                    $count++;
                    $sqlGalleryPart = "update " . $tableName . " set GalleryPart_part  = " . $collection_updated[$key1]['new_GalleryPart_part'] . " where value_id = " . $collection_updated[$key1]['value_id'];
                    $connection->query($sqlGalleryPart);
                }
            }
        } catch (MagentoFrameworkExceptionLocalizedException $e) {
            $messageManager->addError($e->getMessage());
        } catch (RuntimeException $e) {
            $messageManager->addError($e->getMessage());
        } catch (Exception $e) {
            $messageManager->addError($e->getMessage());
        }
    }

//         if (isset($data['product']['media_gallery']['images'])) {
//             $images = $data['product']['media_gallery']['images'];

//             foreach ($images as $image) {
//                 if (isset($image['GalleryPart_part']) && $image['GalleryPart_part'] == 1) {
//                     $galleryPart[$image['value_id']] = 1;
//                 } else {
//                     $galleryPart[$image['value_id']] = 0;
//                 }
//             }
//    // print_r($images);exit;
//             $connection = $this->resource->getConnection();
//             $tableName = 'catalog_product_entity_media_gallery_value'; //gives table name with prefix
//             $product = $observer->getProduct();
//             $mediaGallery = $product->getMediaGallery();

//             if (isset($mediaGallery['images'])) {
//                 foreach ($mediaGallery['images'] as $image) {
//                     if (isset($galleryPart[$image['value_id']])) {
//                         //Update Data into table
//                         $sql = "Update " . $tableName . " Set GalleryPart_part = " . $galleryPart[$image['value_id']] . " where value_id = " . $image['value_id'];
//                         $connection->query($sql);
//                     }
//                 }
//             }
//         }


    }

}

It is not saving the selected dropdown value in ‘GalleryPart_part’ column. Any help would be appreciated.