Hey MuhGuy. I am looking into providers to facility in-app purchases outside of Steam but it has been proving much more difficult than I anticipated. Currently I offer codes through my Patreon to redeem for Pearls. I don't mean to exclude you, and I do want your business. If you're interested I would be happy to give you a steam key for your purchase here on itchio.
I apologies for the situation and thank you for playing. -Din