I used react-native init MyApp to initialise a new React Native app. This created among others an Android project with the package com.myapp.
react-native init MyApp
com.myapp
In VS Code, press Ctrl + Shift + F and enter your old package name in 'Find' and enter your new package in 'Replace'. Then press 'Replace all occurrences'.
Ctrl + Shift + F
Definitely not the pragmatic way. But, it's done the trick for me.