You will probably need to apply some CSS styling in your theme’s stylesheet.
Did you try going to WooCommerce >> Settings >> General tab?
There is an option to set the gift wrapping to be active by default.
See the documentation:
https://github.com/mikejolley/woocommerce-product-gift-wrap
As an addendum, my current idea is that by the time WordPress call for the archive-portfolio template, the pre_get_posts hook has already been executed. Is this correct or is this a different issue?