(urgent) fix bug in React Native iOS app, the bug is the app is completely freezing/unresponsive (read description)

need react native developer who can fix a bug in React Native iOS app, the bug is the app is completely freezing/unresponsive while fetching data from firestore and after user using the app from 3-5 mins app is completely freezing, the bug doesn't exist on play store it's showing on apple store only.
The app is learning English app
I prefer to you have a physical iPhone device to check the bug first before starting.. just tell me to send you the app link
check this video to show one of the screens has the bug.