If I build my mobile app as a Single page application in bubble and then make payment as an iframe. would that be a problem for submitting to the apple store and google play store?
I believe if you redirect to an external web page (via Safari), then probably yes. After some research, you can’t. What I’ve heard is that you need to accept payment only with Apple Store inside your app. You give them the right to analyze your code at any time. They are familiar with this strategy. In the end, they will close your app.
You somewhat have to read between the lines but in my experience if you want to avoid in app purchases, you can’t have any mechanisms within your app to purchase anything other than physical goods. You also can’t have any links to a purchase page or sign up page. Sometimes they don’t even allow a link to an outside page that will eventually lead to a payment page but as with many things, it depends on you reviewer.
If you choose payment outside of AppStore, you can not advertise or have any link in your app that will redirect user out of the app to purchase. One example is Audible.
Netflix and others have been trying to get past the 30% for a while now.