I'm Zuzanna, from the team here at Shopify :)
Right now, the way most recurring subscription apps work is they allow you to keep Shopify Payments as your main payment provider, this will be used for any purchases that aren't recurring within your store. Then they also allow you to set up a payment provider that works with their specific app, along with Shopify Payments. Essentially, you will have two payment providers working alongside each other on your store, one for non-subscription based products and the other for subscription based products.
These apps are all created by third party developers, so if you had any more questions about how that set up works, you can reach out to them directly. Here are some of the apps that will let you do this:
I hope this helps! If you have any more questions or concerns feel free to reach out to us here :)
Have a great one,