A cathartic exercise listing all the tiny cuts that make testing iOS IAPs miserable.
The biggest being with subscriptions, you will have to clear 5-6 login modals every time you unlock your phone. The only fix is uninstalling the app your testing, which is usually the app you are working on.
Neglect of the developer experience runs downhill and consumers are the ones who ultimately suffer. I wish Apple would put some of their massive stockpile of cash into solving these solvable problems.