"Mailing List" of recent entries in Collection

I’m looking for the best way to automatically email my Contacts recent entries in one of my collections as a table or “repeater”. The frequency of these emails will be dependent on each person’s settings: immediately, once per day or once per week.

Initially I was thinking of using a third party service like SendGrid which accepts HTML code for a section in the email template. For instance, I create a GET “HTTP Function” from the backend which queries the “Deals” collection based on a “frequency” variable and then outputs HTML code as part of the payload being sent.

Is this the best option? If so, is there an easy way to create this HTML output?

Is there a way to do this all within Wix?