Do I have to use In-App Purchasing?

So in my app users have an avatar and there is some functionality where users can use their own face scanned 3d model instead of the default avatar head.

Through a third party app our users send us images so the 3d model can be generated (for a fee). Once the face scan is generated we assign it to the user's account where they can use it during play.

The problem with using In-app-purchasing (IAP) in this instance is that the this is a custom feature that requires the user to take action on a third party app to complete the process anyway. It would be a hassle to have to make the user pay with IAP, then go outside the app to send their images, and once the model is generated (takes a few days) hope it was assigned to their proper account.

If I did it where the payment, 3d model generation, and assigning the model to the user took place outside the app would that be a violation of Policy 3.1.1?

Policy 3.1.1 If you want to unlock features or functionality within your app, (by way of example: subscriptions, in-game currencies, game levels, access to premium content, or unlocking a full version), you must use in-app purchase. Apps may not use their own mechanisms to unlock content or functionality, such as license keys, augmented reality markers, QR codes, cryptocurrencies and cryptocurrency wallets, etc.

Do I have to use In-App Purchasing?
 
 
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