How to enable custom multi-vendor checkout on Shopify API Extensions (2.0)

Hi Community,

I am looking to develop a custom checkout page for multi-vendors who might have different shipping methods / delivery areas. With the new announcement of Shopify Unite OS 2.0, there is checkout customization that enables security without running tons of 3rd party scripts on the backend. I am looking to see if it’s possible to develop Shopify custom checkout for multiple vendors without Shopify Plus.

Thanks

Manan