Nothing wrong with Foxy.io, but for your specific situation Shopify Lite is more likely to be the easiest way to integrate Printful while embedding catalogs or single products on your webflow site. You’ll be able to create products inside the Printful Shopify app (very helpful if you have product variants - sizes & colours). I’ve played around with this set up but unfortunately haven’t got anything to share. A few things that bothered me about Shopify embeds are that you lose the product search and filtering functionality typically found on the online Shopify channel (might be achieved with JS Buy SDK) or WooCommerce.
Any code ninjas out there work with Buy SDK?