Using paywall builder to make purchases outside of Apple/Google

Is it possible?

Hi, I want to implement IAP where the Appstore/GooglePlay are not working at the moment, or alternative stores are used. The most suitable candidate is "void paywallViewDidStartPurchase()" from AdaptyUI. All the necessary information is already there, but there is no way to prevent the system IAP dialog from being shown.

Maybe there is some way to start a custom checkout process from paywall builder?