I agree that a single in-app purchase is preferable. However, dividing the cost for extra features might deter users and lead to negative outcomes. Many users value the current one-time purchase model and regular updates. Introducing multiple payments could result in bad reviews and user abandonment. A solution could be raising the full version price for new users and implementing a small one-time fee for existing users. Allowing features, even if unused, with the option to disable them without affecting performance is essential.