That is the solution. Use the store and you do not have to disclose anything. Circumvent and you have to open the books to show sales so Apple can take a reduced fee for providing the shelf space and development tools.Could Apple take a book out of the Epic lawsuit and rule that apps using alternative payments are still liable to pay Apple a percentage of their revenue?
After all, we know that the only real reason why app developers want to use third party payments is to get out of paying Apple 30%, even if they don’t quite say that out loud. This would make for an interesting Pyrrhic victory for these companies - give them the flexibility of using other payment options, but without the convenience or the savings.