The item SKU is a one-of-a-kind id for every item in a Magento 2 store. Changing item SKU in mass is difficult in Magento 2.
Nonetheless, at some point, it might happen that you want to Update Bulk Product SKU Using CSV Magento 2 when you are bringing in items from an outsider stage.
For more info: https://meetanshi.com/blog/update-bulk-product-sku-using-csv-in-magento-2/