Currently, I am developing a subscription app that does not use the subscription API which was recently released and when I was going through the subscription API docs I came to know that it does not support alternate payment for now and my app is already been developed by using payment gateway's subscription API's and need to be released in Shopify app store very shortly. I like to know will my app will be approved or not comparing to this https://shopify.dev/concepts/apps/subscriptions-faq#what-should-i-do-if-i-have-merchants-dependent-o... article and if not what I need to do so that I will be accepted in-app store
Your subscriptions app will not be approved for the app store, if it does not use the Subscriptions API. I understand you are attempting to provide a work-around to add support for alternate payment methods. The only options to be accepted in the app store would be to use the Subscriptions API.