Eject an existing App

I have an existing app that is now having in-app purchases added to it for subscriptions. To use expo-in-app-purchases I needed to eject my app. Things are working as expected on iOS but here’s the snag:

For Android, in order to create an in-app product, I need to upload an APK with Billing permissions. Now that I have to build using Android Studio, I have to create a keystore, not have Expo manage that keystore. Of course, changing the keystore used causes an error when I upload the bundle to the Play store. Has one done this before?