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Magento 2 how to override member variable

We have created custom link types like consumable, recommended, etc like cross-sells, upsells, related.
Now we would like to implement the import functionality for these custom types. We have written below code on vendor file (Magento/CatalogImportExport/Model/Import/Product.php) so that while import custom link types are working as expected.

File Path is: Vendor/Magento/CatalogImportExport/Model/Import/Product.php

 /**
     * Links attribute name-to-link type ID.
     *
     * @var array
     */
    protected $_linkNameToId = [
        '_related_' => MagentoCatalogModelProductLink::LINK_TYPE_RELATED,
        '_crosssell_' => MagentoCatalogModelProductLink::LINK_TYPE_CROSSSELL,
        '_upsell_' => MagentoCatalogModelProductLink::LINK_TYPE_UPSELL,
        '_required_' => StackExchangeRequiredProductModelProductLink::LINK_TYPE_REQUIRED,
        '_consumable_' => StackExchangeAdditionalItemsModelProductLink::LINK_TYPE_CONSUMABLE,
        '_recommended_' => StackExchangeAdditionalItemsModelProductLink::LINK_TYPE_RECOMMENDED,
        '_optional_language_arts_' => StackExchangeAdditionalItemsModelProductLink::LINK_TYPE_OPTIONAL_LANGUAGE_ARTS,
        '_fivedays_also_includes_' => StackExchangeAdditionalItemsModelProductLink::LINK_TYPE_FIVEDAYS_ALSO_INCLUDES
    ];



/**
         * Map between import file fields and system fields/attributes.
         *
         * @var array
         */
    protected $_fieldsMap = [ ......
                                           .......                                         
            '_required_sku' => 'required_skus',
            '_consumable_sku' => 'consumable_skus',
            '_recommended_sku' => 'recommended_skus',
            '_optional_language_arts_sku' => 'optional_language_arts_skus',
            '_fivedays_also_includes_sku' => 'fivedays_also_includes_skus'
        ];

Now I would like to override and add my data from my custom module. Can anyone guide and provide me the steps, please. Magento 2.3.1 Version

My CSV format looks like this:

enter image description here