Elias here with Shopify Support. Thank you for reaching out.
I understand you’re looking to edit the text for the tax and shipping calculated message on your product page. You don’t need to edit the theme’s coding for this, rather you can use the Language editor. The Language editor is located under ‘Online store > Themes > Actions > Edit language’, and you’re able to change the text for the product and checkout pages. In the Language editor, simply search the terms “Shipping calculated” to filter the list of available translations. Then, look for the 'Products / Product’ field and replace the second part of the text with your intended message.