Rakesh Jesadiya

The shipment item record will be available on the Magento 2 sales_shipment_item table.

The table contains the list of shipment item records with the product item level. When you delete the record, a record will be deleted from the sales_shipment_item table.

You can retrieve the shipment item data by shipment item id using Magento 2 by Shipment Item RepositoryInterface.

Used Shipment item repository interface to get shipment data:
Magento\Sales\Api\ShipmentItemRepositoryInterface

You can retrieve partial shipment items collection by Order item id using Magento 2 with the search criteria Builder interface.

This is the rare condition where you need to fetch the list of shipment items from the Order item id.