I really wish Stripe would just make something like this. Just the bare minimum necessary to host Checkout for products entered in your Stripe dashboard. I wonder if they can’t due to some onerous clause in their agreement with Shopify.
Have you done a write it up English for how that works? Does stripe send emails and you just have the emails contain the content as attachments or straight text?
Definitely check them out - they're great. Easyful is just a fulfillment layer that plugs into Stripe payment links for emailing customers your content when they buy something.