Start adding tests
Currently there are no tests whatsoever for the app. In this case testing was sacrificed for time/resources and also in part due to the prototypical nature of the app and lack of commitment to a specific design.
However, now that the app has reached a greater state of maturity it would be a bad idea not to have tests, especially for the state management with Redux (rending-related tests would also be good, but are lower priority).
Expo has some docs on how to implement tests using jest: https://docs.expo.io/guides/testing-with-jest/