Email delivery (incl attachment) automation

Hello, We’re looking to create an automated delivery system for all our orders. We are today selling on Shopify and all our products are delivered as individual and unique attachments by email. First of all, we want an integration from Shopify to an email provider (we are today using Gmail, but we can change if another provider is better to to use for the thing that we are looking for). We want to create a draft with the purchasers email address as the recipient and with the order number as the last part in the subject, just after a certain text which will always be the same. The content in the email should also always be the same. In one way we have found how to do this with Zapier, but we haven’t been able to make it work with our Gmail template, just with ordinary text, which we have written directly on Zapier. We want to use our good looking template when sending our orders to the customers. The second thing we will need is an automation that constantly (or one time every 5min or something like that) are searching for an attachment that is named exactly as the order number and then also as the last word in the draft. This file will always be in the same folder. When the attachment, which matched the order number/the last name in the draft is found and attached, we want the email automatically sent to the customer. Is this something that you have experience with? Or is this something that you could be able to perform? And if you can, what would be the time frame and what is the amount that this would cost us? Please let us know, and also please let us know the questions you have regarding this. Thank you for your time and I hope to hear from you shortly! Kind Regards, Jesper