You can change the Shipping Template for either a single product or multiple products in bulk. You can edit a single product by clicking on the 'Pencil' icon and change the Shipping Template for the product.
If you are looking to change the Shipping Template for similar kind of products in bulk, you need to follow the below steps:
This will change the Shipping Template for your products in bulk. Now to update these shipping data, you will need to re-publish the Active products in order to update the same on Etsy as well.