I have an iOS app that is compatible with Macs with an M chip. It is in a small size when launched, and can be put in full screen. But there is no way to resize the window. How can I achieve that?

I have an app that I am about to release (AnyTracker). It is already available on Android. The App Review team rejected my submission since I use auto-renewing subscriptions in my app. A free user can track from one website, while a Premium user can track from an unlimited number of websites. If the user no longer is Premium (the subscription runs out), he/she can only track from one website again. Premium users can also track stocks and cryptocurrencies multiple times, free users can only do so 1 time. According to the review team, this is "not an appropriate use of the service. Specifically, your in-app purchase products only unlock features." But as I understand the app is providing dynamic value, since as long as the user is subscribed, he/she has access to up-to-date information. Am I missing something here?