Update React Native app page from a Google Sheets and Google Calendar

I am wanting to update two different pages in my app from a Google API. The first is a calendar of events that can be added to the google calendar and will automatically appear on the React Native app.

The next is a numbered list added in Google Sheets that will automatically appear on the React Native app.

Only examples and documentation I can find is for the other way around where there is a form input on the app and it populates the data to Google.

This is basically what I want to do but I would format mine a little different. https://www.youtube.com/watch?v=o2RFdhnMXBM