Shopify as a customer management system & dashboard

Hi, I am in the process of launching a new business. It is a SAAS which is accessible to the user through a web app. The app has been built & is ready for launch.

I am looking for a way to manage the customers + orders + view analytics through a backend dashboard. Essentially just to track the users orders, cancel orders/subscriptions, have contact information and create new users.
Is it possible to integrate shopify to an already created app? Is it best to do this & use shopify at the part of payments to achieve this?

Thanks in advance!